21161260197 has 72 divisors (see below), whose sum is σ = 38876321952. Its totient is φ = 10968148800.

The previous prime is 21161260171. The next prime is 21161260217. The reversal of 21161260197 is 79106216112.

21161260197 is a `hidden beast` number, since 21 + 1 + 612 + 6 + 0 + 19 + 7 = 666.

It is not a de Polignac number, because 21161260197 - 2⁷ = 21161260069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21161261197) 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 71 ways as a sum of consecutive naturals, for example, 2260747 + ... + 2270087.

It is an arithmetic number, because the mean of its divisors is an integer number (539948916).

Almost surely, 2^21161260197 is an apocalyptic number.

It is an amenable number.

21161260197 is a deficient number, since it is larger than the sum of its proper divisors (17715061755).

21161260197 is a wasteful number, since it uses less digits than its factorization.

21161260197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9839 (or 9829 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

The spelling of 21161260197 in words is "twenty-one billion, one hundred sixty-one million, two hundred sixty thousand, one hundred ninety-seven".