21557452 has 18 divisors (see below), whose sum is σ = 43885212. Its totient is φ = 9238824.

The previous prime is 21557447. The next prime is 21557453. The reversal of 21557452 is 25475512.

It is not an unprimeable number, because it can be changed into a prime (21557453) 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 5 ways as a sum of consecutive naturals, for example, 54798 + ... + 55189.

Almost surely, 2^21557452 is an apocalyptic number.

It is an amenable number.

21557452 is an abundant number, since it is smaller than the sum of its proper divisors (22327760).

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

21557452 is a wasteful number, since it uses less digits than its factorization.

21557452 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110005 (or 109996 counting only the distinct ones).

The product of its digits is 14000, while the sum is 31.

The square root of 21557452 is about 4643.0003230670. Note that the first 3 decimals coincide. The cubic root of 21557452 is about 278.3123484085.

The spelling of 21557452 in words is "twenty-one million, five hundred fifty-seven thousand, four hundred fifty-two".