21255552 has 48 divisors (see below), whose sum is σ = 61168380. Its totient is φ = 7084800.

The previous prime is 21255541. The next prime is 21255557. The reversal of 21255552 is 25555212.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255557) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8074 + ... + 10377.

Almost surely, 2^21255552 is an apocalyptic number.

It is an amenable number.

21255552 is an abundant number, since it is smaller than the sum of its proper divisors (39912828).

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

21255552 is a wasteful number, since it uses less digits than its factorization.

21255552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18471 (or 18456 counting only the distinct ones).

The product of its digits is 5000, while the sum is 27.

The square root of 21255552 is about 4610.3743882683. The cubic root of 21255552 is about 277.0070332334.

The spelling of 21255552 in words is "twenty-one million, two hundred fifty-five thousand, five hundred fifty-two".