21128952 has 64 divisors (see below), whose sum is σ = 57324960. Its totient is φ = 6451200.

The previous prime is 21128941. The next prime is 21128957. The reversal of 21128952 is 25982112.

It is a super-2 number, since 2×21128952² = 892865225236608, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21128957) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 75052 + ... + 75332.

Almost surely, 2^21128952 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 21128952, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28662480).

21128952 is an abundant number, since it is smaller than the sum of its proper divisors (36196008).

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

21128952 is a wasteful number, since it uses less digits than its factorization.

21128952 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 544 (or 540 counting only the distinct ones).

The product of its digits is 2880, while the sum is 30.

The square root of 21128952 is about 4596.6239785303. The cubic root of 21128952 is about 276.4559780454.

The spelling of 21128952 in words is "twenty-one million, one hundred twenty-eight thousand, nine hundred fifty-two".