21082904 has 32 divisors (see below), whose sum is σ = 41580000. Its totient is φ = 10002432.

The previous prime is 21082903. The next prime is 21082939. The reversal of 21082904 is 40928012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21082903) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27032 + ... + 27800.

It is an arithmetic number, because the mean of its divisors is an integer number (1299375).

Almost surely, 2^21082904 is an apocalyptic number.

It is an amenable number.

21082904 is a deficient number, since it is larger than the sum of its proper divisors (20497096).

21082904 is a wasteful number, since it uses less digits than its factorization.

21082904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 947 (or 943 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 21082904 is about 4591.6123529758. The cubic root of 21082904 is about 276.2549978280.

The spelling of 21082904 in words is "twenty-one million, eighty-two thousand, nine hundred four".