21161500972 has 24 divisors (see below), whose sum is σ = 38277706320. Its totient is φ = 10230893760.

The previous prime is 21161500967. The next prime is 21161500973. The reversal of 21161500972 is 27900516112.

It is not an unprimeable number, because it can be changed into a prime (21161500973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 720583 + ... + 749374.

It is an arithmetic number, because the mean of its divisors is an integer number (1594904430).

Almost surely, 2^21161500972 is an apocalyptic number.

It is an amenable number.

21161500972 is a deficient number, since it is larger than the sum of its proper divisors (17116205348).

21161500972 is a wasteful number, since it uses less digits than its factorization.

21161500972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1470081 (or 1470079 counting only the distinct ones).

The product of its (nonzero) digits is 7560, while the sum is 34.

The spelling of 21161500972 in words is "twenty-one billion, one hundred sixty-one million, five hundred thousand, nine hundred seventy-two".