16306921 has 4 divisors (see below), whose sum is σ = 17165200. Its totient is φ = 15448644.

The previous prime is 16306897. The next prime is 16306937. The reversal of 16306921 is 12960361.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12960361 = 29 ⋅446909.

It is a cyclic number.

It is not a de Polignac number, because 16306921 - 2¹³ = 16298729 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 16306921.

It is not an unprimeable number, because it can be changed into a prime (16306981) 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, 429111 + ... + 429148.

It is an arithmetic number, because the mean of its divisors is an integer number (4291300).

Almost surely, 2^16306921 is an apocalyptic number.

It is an amenable number.

16306921 is a deficient number, since it is larger than the sum of its proper divisors (858279).

16306921 is an equidigital number, since it uses as much as digits as its factorization.

16306921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 858278.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 16306921 is about 4038.1828834267. The cubic root of 16306921 is about 253.5852501398.

The spelling of 16306921 in words is "sixteen million, three hundred six thousand, nine hundred twenty-one".