21532388 has 12 divisors (see below), whose sum is σ = 37766652. Its totient is φ = 10741920.

The previous prime is 21532373. The next prime is 21532403. The reversal of 21532388 is 88323512.

It is an interprime number because it is at equal distance from previous prime (21532373) and next prime (21532403).

It can be written as a sum of positive squares in 2 ways, for example, as 13017664 + 8514724 = 3608^2 + 2918^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3995 + ... + 7682.

It is an arithmetic number, because the mean of its divisors is an integer number (3147221).

Almost surely, 2^21532388 is an apocalyptic number.

It is an amenable number.

21532388 is a deficient number, since it is larger than the sum of its proper divisors (16234264).

21532388 is a wasteful number, since it uses less digits than its factorization.

21532388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12142 (or 12140 counting only the distinct ones).

The product of its digits is 11520, while the sum is 32.

The square root of 21532388 is about 4640.3004213089. The cubic root of 21532388 is about 278.2044456459.

The spelling of 21532388 in words is "twenty-one million, five hundred thirty-two thousand, three hundred eighty-eight".