21001907970 has 48 divisors (see below), whose sum is σ = 54759731832. Its totient is φ = 5584634880.

The previous prime is 21001907951. The next prime is 21001907977. The reversal of 21001907970 is 7970910012.

It can be written as a sum of positive squares in 4 ways, for example, as 18731480769 + 2270427201 = 136863^2 + 47649^2 .

It is not an unprimeable number, because it can be changed into a prime (21001907977) by changing a digit.

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, 298761 + ... + 362300.

Almost surely, 2^21001907970 is an apocalyptic number.

21001907970 is an abundant number, since it is smaller than the sum of its proper divisors (33757823862).

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

21001907970 is a wasteful number, since it uses less digits than its factorization.

21001907970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 661427 (or 661424 counting only the distinct ones).

The product of its (nonzero) digits is 7938, while the sum is 36.

The spelling of 21001907970 in words is "twenty-one billion, one million, nine hundred seven thousand, nine hundred seventy".