23121021 has 32 divisors (see below), whose sum is σ = 38854656. Its totient is φ = 11880000.

The previous prime is 23121011. The next prime is 23121031. The reversal of 23121021 is 12012132.

Added to its reverse (12012132) it gives a triangular number (35133153 = T₈₃₈₂).

It is an interprime number because it is at equal distance from previous prime (23121011) and next prime (23121031).

It is not a de Polignac number, because 23121021 - 2⁵ = 23120989 is a prime.

It is a super-2 number, since 2×23121021² = 1069163224164882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 23120988 and 23121006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23121011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 22836 + ... + 23826.

It is an arithmetic number, because the mean of its divisors is an integer number (1214208).

Almost surely, 2^23121021 is an apocalyptic number.

23121021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

23121021 is a deficient number, since it is larger than the sum of its proper divisors (15733635).

23121021 is a wasteful number, since it uses less digits than its factorization.

23121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1113.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 23121021 is about 4808.4322808999. The cubic root of 23121021 is about 284.8846193462.

Adding to 23121021 its reverse (12012132), we get a palindrome (35133153).

Subtracting from 23121021 its reverse (12012132), we obtain a square (11108889 = 3333²).

It can be divided in two parts, 2312 and 1021, that added together give a palindrome (3333).

The spelling of 23121021 in words is "twenty-three million, one hundred twenty-one thousand, twenty-one".