21135239460 has 72 divisors (see below), whose sum is σ = 67881425976. Its totient is φ = 5304529920.

The previous prime is 21135239441. The next prime is 21135239473. The reversal of 21135239460 is 6493253112.

21135239460 is a `hidden beast` number, since 2 + 113 + 52 + 39 + 460 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 5987045376 + 15148194084 = 77376^2 + 123078^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3450411 + ... + 3456530.

It is an arithmetic number, because the mean of its divisors is an integer number (942797583).

Almost surely, 2^21135239460 is an apocalyptic number.

21135239460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21135239460 is an abundant number, since it is smaller than the sum of its proper divisors (46746186516).

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

21135239460 is a wasteful number, since it uses less digits than its factorization.

21135239460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6906973 (or 6906968 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The spelling of 21135239460 in words is "twenty-one billion, one hundred thirty-five million, two hundred thirty-nine thousand, four hundred sixty".