21125145600 has 528 divisors, whose sum is σ = 83580483840. Its totient is φ = 5197824000.

The previous prime is 21125145599. The next prime is 21125145619. The reversal of 21125145600 is 654152112.

21125145600 is a `hidden beast` number, since 2 + 1 + 1 + 2 + 51 + 4 + 5 + 600 = 666.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 8984425 + ... + 8986775.

Almost surely, 2^21125145600 is an apocalyptic number.

21125145600 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 21125145600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41790241920).

21125145600 is an abundant number, since it is smaller than the sum of its proper divisors (62455338240).

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

21125145600 is a wasteful number, since it uses less digits than its factorization.

21125145600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2403 (or 2374 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

Adding to 21125145600 its reverse (654152112), we get a palindrome (21779297712).

The spelling of 21125145600 in words is "twenty-one billion, one hundred twenty-five million, one hundred forty-five thousand, six hundred".