21865473 has 12 divisors (see below), whose sum is σ = 36095488. Its totient is φ = 12494520.

The previous prime is 21865469. The next prime is 21865531. The reversal of 21865473 is 37456812.

21865473 is a `hidden beast` number, since 2 + 186 + 5 + 473 = 666.

It is not a de Polignac number, because 21865473 - 2² = 21865469 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21865573) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 173473 + ... + 173598.

Almost surely, 2^21865473 is an apocalyptic number.

It is an amenable number.

21865473 is a deficient number, since it is larger than the sum of its proper divisors (14230015).

21865473 is a wasteful number, since it uses less digits than its factorization.

21865473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 347084 (or 347081 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 21865473 is about 4676.0531434106. The cubic root of 21865473 is about 279.6316286741.

The spelling of 21865473 in words is "twenty-one million, eight hundred sixty-five thousand, four hundred seventy-three".