21135747672 has 96 divisors (see below), whose sum is σ = 63634596480. Its totient is φ = 6293514240.

The previous prime is 21135747667. The next prime is 21135747697. The reversal of 21135747672 is 27674753112.

21135747672 is a `hidden beast` number, since 2 + 1 + 1 + 3 + 574 + 7 + 6 + 72 = 666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 335193 + ... + 393224.

It is an arithmetic number, because the mean of its divisors is an integer number (662860380).

Almost surely, 2^21135747672 is an apocalyptic number.

It is an amenable number.

21135747672 is an abundant number, since it is smaller than the sum of its proper divisors (42498848808).

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

21135747672 is a wasteful number, since it uses less digits than its factorization.

21135747672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 728473 (or 728466 counting only the distinct ones).

The product of its digits is 493920, while the sum is 45.

The spelling of 21135747672 in words is "twenty-one billion, one hundred thirty-five million, seven hundred forty-seven thousand, six hundred seventy-two".