21125514400 has 72 divisors (see below), whose sum is σ = 51871109724. Its totient is φ = 8401305600.

The previous prime is 21125514379. The next prime is 21125514407. The reversal of 21125514400 is 441552112.

It can be written as a sum of positive squares in 6 ways, for example, as 6058442896 + 15067071504 = 77836^2 + 122748^2 .

It is a Harshad number since it is a multiple of its sum of digits (25).

It is not an unprimeable number, because it can be changed into a prime (21125514407) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 62080 + ... + 214720.

Almost surely, 2^21125514400 is an apocalyptic number.

21125514400 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 21125514400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25935554862).

21125514400 is an abundant number, since it is smaller than the sum of its proper divisors (30745595324).

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

21125514400 is a wasteful number, since it uses less digits than its factorization.

21125514400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152834 (or 152821 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 25.

The spelling of 21125514400 in words is "twenty-one billion, one hundred twenty-five million, five hundred fourteen thousand, four hundred".