21073923 has 24 divisors (see below), whose sum is σ = 33917520. Its totient is φ = 12519360.

The previous prime is 21073919. The next prime is 21073933. The reversal of 21073923 is 32937012.

It is not a de Polignac number, because 21073923 - 2² = 21073919 is a prime.

It is a super-2 number, since 2×21073923² = 888220461219858, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21073933) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 288 + ... + 6498.

It is an arithmetic number, because the mean of its divisors is an integer number (1413230).

Almost surely, 2^21073923 is an apocalyptic number.

21073923 is a deficient number, since it is larger than the sum of its proper divisors (12843597).

21073923 is a wasteful number, since it uses less digits than its factorization.

21073923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6259 (or 6256 counting only the distinct ones).

The product of its (nonzero) digits is 2268, while the sum is 27.

The square root of 21073923 is about 4590.6342699021. The cubic root of 21073923 is about 276.2157654320.

The spelling of 21073923 in words is "twenty-one million, seventy-three thousand, nine hundred twenty-three".