21264021600 has 144 divisors (see below), whose sum is σ = 73285965648. Its totient is φ = 5336842240.

The previous prime is 21264021557. The next prime is 21264021629. The reversal of 21264021600 is 612046212.

It is a super-2 number, since 2×21264021600² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 219789 + ... + 301388.

It is an arithmetic number, because the mean of its divisors is an integer number (508930317).

Almost surely, 2^21264021600 is an apocalyptic number.

21264021600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21264021600 is an abundant number, since it is smaller than the sum of its proper divisors (52021944048).

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

21264021600 is a wasteful number, since it uses less digits than its factorization.

21264021600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 521217 (or 521204 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

Adding to 21264021600 its reverse (612046212), we get a palindrome (21876067812).

The spelling of 21264021600 in words is "twenty-one billion, two hundred sixty-four million, twenty-one thousand, six hundred".