30921399 has 16 divisors (see below), whose sum is σ = 45911040. Its totient is φ = 20568600.

The previous prime is 30921391. The next prime is 30921427. The reversal of 30921399 is 99312903.

It is not a de Polignac number, because 30921399 - 2³ = 30921391 is a prime.

It is a super-2 number, since 2×30921399² = 1912265832234402, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30921391) 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 15 ways as a sum of consecutive naturals, for example, 14874 + ... + 16824.

It is an arithmetic number, because the mean of its divisors is an integer number (2869440).

Almost surely, 2^30921399 is an apocalyptic number.

30921399 is a deficient number, since it is larger than the sum of its proper divisors (14989641).

30921399 is a wasteful number, since it uses less digits than its factorization.

30921399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2547 (or 2541 counting only the distinct ones).

The product of its (nonzero) digits is 13122, while the sum is 36.

The square root of 30921399 is about 5560.7013046917. The cubic root of 30921399 is about 313.8723398184.

The spelling of 30921399 in words is "thirty million, nine hundred twenty-one thousand, three hundred ninety-nine".