81157652991650 has 24 divisors (see below), whose sum is σ = 151735375694244. Its totient is φ = 32294858803200.

The previous prime is 81157652991601. The next prime is 81157652991691. The reversal of 81157652991650 is 5619925675118.

81157652991650 is digitally balanced in base 3, 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 6 ways, for example, as 27116379460921 + 54041273530729 = 5207339^2 + 7351277^2 .

It is a super-2 number, since 2×81157652991650² (a number of 29 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, 4205050091 + ... + 4205069390.

Almost surely, 2^{81157652991650} is an apocalyptic number.

81157652991650 is a deficient number, since it is larger than the sum of its proper divisors (70577722702594).

81157652991650 is a wasteful number, since it uses less digits than its factorization.

81157652991650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8410119686 (or 8410119681 counting only the distinct ones).

The product of its (nonzero) digits is 40824000, while the sum is 65.

The spelling of 81157652991650 in words is "eighty-one trillion, one hundred fifty-seven billion, six hundred fifty-two million, nine hundred ninety-one thousand, six hundred fifty".