21587473 has 8 divisors (see below), whose sum is σ = 22052160. Its totient is φ = 21126480.

The previous prime is 21587453. The next prime is 21587491. The reversal of 21587473 is 37478512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21587473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21587453) 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, 13068 + ... + 14626.

It is an arithmetic number, because the mean of its divisors is an integer number (2756520).

Almost surely, 2^21587473 is an apocalyptic number.

It is an amenable number.

21587473 is a deficient number, since it is larger than the sum of its proper divisors (464687).

21587473 is a wasteful number, since it uses less digits than its factorization.

21587473 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1847.

The product of its digits is 47040, while the sum is 37.

The square root of 21587473 is about 4646.2321293711. The cubic root of 21587473 is about 278.4414814728.

The spelling of 21587473 in words is "twenty-one million, five hundred eighty-seven thousand, four hundred seventy-three".