21939534400 has 315 divisors, whose sum is σ = 65653321449. Its totient is φ = 7195077120.

The previous prime is 21939534389. The next prime is 21939534437. The reversal of 21939534400 is 443593912.

The square root of 21939534400 is 148120.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 7898232384 + 14041302016 = 88872^2 + 118496^2 .

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 953892789 + ... + 953892811.

Almost surely, 2^21939534400 is an apocalyptic number.

21939534400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

21939534400 is the 148120-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21939534400

21939534400 is an abundant number, since it is smaller than the sum of its proper divisors (43713787049).

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

21939534400 is an frugal number, since it uses more digits than its factorization.

21939534400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128 (or 37 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 40.

The spelling of 21939534400 in words is "twenty-one billion, nine hundred thirty-nine million, five hundred thirty-four thousand, four hundred".