21102431 has 8 divisors (see below), whose sum is σ = 25165824. Its totient is φ = 17301240.

The previous prime is 21102421. The next prime is 21102439. The reversal of 21102431 is 13420112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21102431 - 2¹⁰ = 21101407 is a prime.

It is a super-2 number, since 2×21102431² = 890625188219522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 65375 + ... + 65696.

It is an arithmetic number, because the mean of its divisors is an integer number (3145728).

Almost surely, 2^21102431 is an apocalyptic number.

21102431 is a deficient number, since it is larger than the sum of its proper divisors (4063393).

21102431 is a wasteful number, since it uses less digits than its factorization.

21102431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131101.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 21102431 is about 4593.7382380802. The cubic root of 21102431 is about 276.3402606988.

Adding to 21102431 its reverse (13420112), we get a palindrome (34522543).

The spelling of 21102431 in words is "twenty-one million, one hundred two thousand, four hundred thirty-one".