21153125544520 has 64 divisors (see below), whose sum is σ = 50224445020800. Its totient is φ = 7995931315200.

The previous prime is 21153125544517. The next prime is 21153125544541. The reversal of 21153125544520 is 2544552135112.

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

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34399804 + ... + 35009323.

It is an arithmetic number, because the mean of its divisors is an integer number (784756953450).

Almost surely, 2^{21153125544520} is an apocalyptic number.

21153125544520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21153125544520 is an abundant number, since it is smaller than the sum of its proper divisors (29071319476280).

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

21153125544520 is a wasteful number, since it uses less digits than its factorization.

21153125544520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69409558 (or 69409554 counting only the distinct ones).

The product of its (nonzero) digits is 240000, while the sum is 40.

Adding to 21153125544520 its reverse (2544552135112), we get a palindrome (23697677679632).

The spelling of 21153125544520 in words is "twenty-one trillion, one hundred fifty-three billion, one hundred twenty-five million, five hundred forty-four thousand, five hundred twenty".