21523572 has 36 divisors (see below), whose sum is σ = 62179936. Its totient is φ = 6149520.

The previous prime is 21523571. The next prime is 21523573. The reversal of 21523572 is 27532512.

It is an interprime number because it is at equal distance from previous prime (21523571) and next prime (21523573).

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21523571) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 42454 + ... + 42957.

Almost surely, 2^21523572 is an apocalyptic number.

It is an amenable number.

21523572 is an abundant number, since it is smaller than the sum of its proper divisors (40656364).

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

21523572 is a wasteful number, since it uses less digits than its factorization.

21523572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85428 (or 85423 counting only the distinct ones).

The product of its digits is 4200, while the sum is 27.

The square root of 21523572 is about 4639.3503855605. The cubic root of 21523572 is about 278.1664720718.

The spelling of 21523572 in words is "twenty-one million, five hundred twenty-three thousand, five hundred seventy-two".