21455252 has 24 divisors (see below), whose sum is σ = 46212096. Its totient is φ = 8487648.

The previous prime is 21455183. The next prime is 21455257. The reversal of 21455252 is 25255412.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21455257) 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 7 ways as a sum of consecutive naturals, for example, 29108 + ... + 29835.

It is an arithmetic number, because the mean of its divisors is an integer number (1925504).

Almost surely, 2^21455252 is an apocalyptic number.

It is an amenable number.

21455252 is an abundant number, since it is smaller than the sum of its proper divisors (24756844).

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

21455252 is a wasteful number, since it uses less digits than its factorization.

21455252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58967 (or 58965 counting only the distinct ones).

The product of its digits is 4000, while the sum is 26.

The square root of 21455252 is about 4631.9814334688. The cubic root of 21455252 is about 277.8718419685.

The spelling of 21455252 in words is "twenty-one million, four hundred fifty-five thousand, two hundred fifty-two".