21532756 has 36 divisors (see below), whose sum is σ = 44577876. Its totient is φ = 9072000.

The previous prime is 21532747. The next prime is 21532781. The reversal of 21532756 is 65723512.

It can be written as a sum of positive squares in 2 ways, for example, as 1587600 + 19945156 = 1260^2 + 4466^2 .

It is a super-3 number, since 3×21532756³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11056 + ... + 12856.

Almost surely, 2^21532756 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21532756, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22288938).

21532756 is an abundant number, since it is smaller than the sum of its proper divisors (23045120).

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

21532756 is a wasteful number, since it uses less digits than its factorization.

21532756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1880 (or 1871 counting only the distinct ones).

The product of its digits is 12600, while the sum is 31.

The square root of 21532756 is about 4640.3400737446. The cubic root of 21532756 is about 278.2060305244.

The spelling of 21532756 in words is "twenty-one million, five hundred thirty-two thousand, seven hundred fifty-six".