21620822400 has 384 divisors, whose sum is σ = 81864180000. Its totient is φ = 5566095360.

The previous prime is 21620822383. The next prime is 21620822423. The reversal of 21620822400 is 422802612.

It is a happy number.

21620822400 is a `hidden beast` number, since 216 + 20 + 8 + 22 + 400 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a super-2 number, since 2×21620822400² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2501286 + ... + 2509914.

Almost surely, 2^21620822400 is an apocalyptic number.

21620822400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21620822400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40932090000).

21620822400 is an abundant number, since it is smaller than the sum of its proper divisors (60243357600).

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

21620822400 is a wasteful number, since it uses less digits than its factorization.

21620822400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8691 (or 8668 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The spelling of 21620822400 in words is "twenty-one billion, six hundred twenty million, eight hundred twenty-two thousand, four hundred".