12691661217570 has 24 divisors (see below), whose sum is σ = 32998319165916. Its totient is φ = 3384442991328.

The previous prime is 12691661217541. The next prime is 12691661217583. The reversal of 12691661217570 is 7571216619621.

12691661217570 is a `hidden beast` number, since 1 + 2 + 6 + 9 + 1 + 6 + 61 + 2 + 1 + 7 + 570 = 666.

12691661217570 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 11743088458761 + 948572758809 = 3426819^2 + 973947^2 .

It is a super-2 number, since 2×12691661217570² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 70509228897 + ... + 70509229076.

Almost surely, 2^{12691661217570} is an apocalyptic number.

12691661217570 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

12691661217570 is an abundant number, since it is smaller than the sum of its proper divisors (20306657948346).

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

12691661217570 is a wasteful number, since it uses less digits than its factorization.

12691661217570 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141018457986 (or 141018457983 counting only the distinct ones).

The product of its (nonzero) digits is 1905120, while the sum is 54.

The spelling of 12691661217570 in words is "twelve trillion, six hundred ninety-one billion, six hundred sixty-one million, two hundred seventeen thousand, five hundred seventy".