21400252 has 12 divisors (see below), whose sum is σ = 37978416. Its totient is φ = 10549280.

The previous prime is 21400219. The next prime is 21400271. The reversal of 21400252 is 25200412.

It is a plaindrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37393 + ... + 37960.

It is an arithmetic number, because the mean of its divisors is an integer number (3164868).

Almost surely, 2^21400252 is an apocalyptic number.

It is an amenable number.

21400252 is a deficient number, since it is larger than the sum of its proper divisors (16578164).

21400252 is a wasteful number, since it uses less digits than its factorization.

21400252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75428 (or 75426 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 21400252 is about 4626.0406396831. The cubic root of 21400252 is about 277.6341996251.

Adding to 21400252 its product of nonzero digits (160), we get a palindrome (21400412).

Adding to 21400252 its reverse (25200412), we get a palindrome (46600664).

The spelling of 21400252 in words is "twenty-one million, four hundred thousand, two hundred fifty-two".