21152400 has 60 divisors (see below), whose sum is σ = 67762032. Its totient is φ = 5640320.

The previous prime is 21152399. The next prime is 21152413. The reversal of 21152400 is 425112.

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21152400.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7614 + ... + 10013.

Almost surely, 2^21152400 is an apocalyptic number.

21152400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21152400 is an abundant number, since it is smaller than the sum of its proper divisors (46609632).

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

21152400 is a wasteful number, since it uses less digits than its factorization.

21152400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17648 (or 17637 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21152400 is about 4599.1738388541. The cubic root of 21152400 is about 276.5582065470.

Adding to 21152400 its reverse (425112), we get a palindrome (21577512).

The spelling of 21152400 in words is "twenty-one million, one hundred fifty-two thousand, four hundred".