21756484 has 12 divisors (see below), whose sum is σ = 38444224. Its totient is φ = 10772424.

The previous prime is 21756461. The next prime is 21756487. The reversal of 21756484 is 48465712.

It is not an unprimeable number, because it can be changed into a prime (21756487) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25992 + ... + 26815.

Almost surely, 2^21756484 is an apocalyptic number.

It is an amenable number.

21756484 is a deficient number, since it is larger than the sum of its proper divisors (16687740).

21756484 is a wasteful number, since it uses less digits than its factorization.

21756484 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52914 (or 52912 counting only the distinct ones).

The product of its digits is 53760, while the sum is 37.

The square root of 21756484 is about 4664.3846325105. The cubic root of 21756484 is about 279.1662442804.

The spelling of 21756484 in words is "twenty-one million, seven hundred fifty-six thousand, four hundred eighty-four".