21222142400 has 84 divisors (see below), whose sum is σ = 52388871600. Its totient is φ = 8461363200.

The previous prime is 21222142387. The next prime is 21222142427. The reversal of 21222142400 is 424122212.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

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, 476276 + ... + 518924.

Almost surely, 2^21222142400 is an apocalyptic number.

21222142400 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 21222142400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26194435800).

21222142400 is an abundant number, since it is smaller than the sum of its proper divisors (31166729200).

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

21222142400 is a wasteful number, since it uses less digits than its factorization.

21222142400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42982 (or 42967 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 21222142400 its reverse (424122212), we get a palindrome (21646264612).

The spelling of 21222142400 in words is "twenty-one billion, two hundred twenty-two million, one hundred forty-two thousand, four hundred".