16121021 has 4 divisors (see below), whose sum is σ = 18424032. Its totient is φ = 13818012.

The previous prime is 16120967. The next prime is 16121029. The reversal of 16121021 is 12012161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 16121021 - 2¹⁸ = 15858877 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 16120987 and 16121005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16121029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1151495 + ... + 1151508.

It is an arithmetic number, because the mean of its divisors is an integer number (4606008).

Almost surely, 2^16121021 is an apocalyptic number.

It is an amenable number.

16121021 is a deficient number, since it is larger than the sum of its proper divisors (2303011).

16121021 is an equidigital number, since it uses as much as digits as its factorization.

16121021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2303010.

The product of its (nonzero) digits is 24, while the sum is 14.

The square root of 16121021 is about 4015.0991270453. The cubic root of 16121021 is about 252.6179353004.

Adding to 16121021 its reverse (12012161), we get a palindrome (28133182).

The spelling of 16121021 in words is "sixteen million, one hundred twenty-one thousand, twenty-one".