21135799908 has 24 divisors (see below), whose sum is σ = 54796518560. Its totient is φ = 7045266600.

The previous prime is 21135799897. The next prime is 21135799931. The reversal of 21135799908 is 80999753112.

It is a Harshad number since it is a multiple of its sum of digits (54).

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 7 ways as a sum of consecutive naturals, for example, 97850818 + ... + 97851033.

Almost surely, 2^21135799908 is an apocalyptic number.

It is an amenable number.

21135799908 is an abundant number, since it is smaller than the sum of its proper divisors (33660718652).

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

21135799908 is a wasteful number, since it uses less digits than its factorization.

21135799908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195701864 (or 195701856 counting only the distinct ones).

The product of its (nonzero) digits is 1224720, while the sum is 54.

The spelling of 21135799908 in words is "twenty-one billion, one hundred thirty-five million, seven hundred ninety-nine thousand, nine hundred eight".