21487746 has 32 divisors (see below), whose sum is σ = 51701760. Its totient is φ = 5816016.

The previous prime is 21487717. The next prime is 21487751. The reversal of 21487746 is 64778412.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12666 + ... + 14261.

It is an arithmetic number, because the mean of its divisors is an integer number (1615680).

Almost surely, 2^21487746 is an apocalyptic number.

21487746 is an abundant number, since it is smaller than the sum of its proper divisors (30214014).

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

21487746 is a wasteful number, since it uses less digits than its factorization.

21487746 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26958.

The product of its digits is 75264, while the sum is 39.

The square root of 21487746 is about 4635.4876766097. The cubic root of 21487746 is about 278.0120502687.

The spelling of 21487746 in words is "twenty-one million, four hundred eighty-seven thousand, seven hundred forty-six".