21587012 has 12 divisors (see below), whose sum is σ = 37902480. Its totient is φ = 10757736.

The previous prime is 21586997. The next prime is 21587017. The reversal of 21587012 is 21078512.

It is not an unprimeable number, because it can be changed into a prime (21587017) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7562 + ... + 10017.

It is an arithmetic number, because the mean of its divisors is an integer number (3158540).

Almost surely, 2^21587012 is an apocalyptic number.

It is an amenable number.

21587012 is a deficient number, since it is larger than the sum of its proper divisors (16315468).

21587012 is a wasteful number, since it uses less digits than its factorization.

21587012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17890 (or 17888 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 26.

The square root of 21587012 is about 4646.1825190149. The cubic root of 21587012 is about 278.4394994215.

The spelling of 21587012 in words is "twenty-one million, five hundred eighty-seven thousand, twelve".