21537425520075 has 24 divisors (see below), whose sum is σ = 35625754292400. Its totient is φ = 11481075084160.

The previous prime is 21537425520071. The next prime is 21537425520101. The reversal of 21537425520075 is 57002552473512.

It is a happy number.

It is not a de Polignac number, because 21537425520075 - 2² = 21537425520071 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21537425520071) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 69242040 + ... + 69552389.

It is an arithmetic number, because the mean of its divisors is an integer number (1484406428850).

Almost surely, 2^{21537425520075} is an apocalyptic number.

21537425520075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21537425520075 is a deficient number, since it is larger than the sum of its proper divisors (14088328772325).

21537425520075 is a wasteful number, since it uses less digits than its factorization.

21537425520075 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138796511 (or 138796506 counting only the distinct ones).

The product of its (nonzero) digits is 2940000, while the sum is 48.

Adding to 21537425520075 its reverse (57002552473512), we get a palindrome (78539977993587).

The spelling of 21537425520075 in words is "twenty-one trillion, five hundred thirty-seven billion, four hundred twenty-five million, five hundred twenty thousand, seventy-five".