21587274 has 24 divisors (see below), whose sum is σ = 47567520. Its totient is φ = 7073448.

The previous prime is 21587273. The next prime is 21587311. The reversal of 21587274 is 47278512.

21587274 is a `hidden beast` number, since 2 + 1 + 587 + 2 + 74 = 666.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21587273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9102 + ... + 11225.

It is an arithmetic number, because the mean of its divisors is an integer number (1981980).

Almost surely, 2^21587274 is an apocalyptic number.

21587274 is an abundant number, since it is smaller than the sum of its proper divisors (25980246).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21587274 is a wasteful number, since it uses less digits than its factorization.

21587274 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20394 (or 20391 counting only the distinct ones).

The product of its digits is 31360, while the sum is 36.

The square root of 21587274 is about 4646.2107141196. The cubic root of 21587274 is about 278.4406258837.

The spelling of 21587274 in words is "twenty-one million, five hundred eighty-seven thousand, two hundred seventy-four".