21013435125 has 80 divisors (see below), whose sum is σ = 39728392704. Its totient is φ = 11048940000.

The previous prime is 21013435117. The next prime is 21013435141. The reversal of 21013435125 is 52153431012.

21013435125 is a `hidden beast` number, since 2 + 10 + 134 + 3 + 512 + 5 = 666.

It is not a de Polignac number, because 21013435125 - 2³ = 21013435117 is a prime.

It is a super-3 number, since 3×21013435125³ (a number of 32 digits) contains 333 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 704260 + ... + 733490.

Almost surely, 2^21013435125 is an apocalyptic number.

21013435125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21013435125 is a deficient number, since it is larger than the sum of its proper divisors (18714957579).

21013435125 is an equidigital number, since it uses as much as digits as its factorization.

21013435125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29329 (or 29310 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

Adding to 21013435125 its reverse (52153431012), we get a palindrome (73166866137).

The spelling of 21013435125 in words is "twenty-one billion, thirteen million, four hundred thirty-five thousand, one hundred twenty-five".