81667213497 has 16 divisors (see below), whose sum is σ = 121011288960. Its totient is φ = 54434538000.

The previous prime is 81667213487. The next prime is 81667213501. The reversal of 81667213497 is 79431276618.

81667213497 is a `hidden beast` number, since 81 + 6 + 6 + 72 + 1 + 3 + 497 = 666.

It is not a de Polignac number, because 81667213497 - 2⁸ = 81667213241 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81667213477) 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 15 ways as a sum of consecutive naturals, for example, 138154 + ... + 427107.

It is an arithmetic number, because the mean of its divisors is an integer number (7563205560).

Almost surely, 2^81667213497 is an apocalyptic number.

It is an amenable number.

81667213497 is a deficient number, since it is larger than the sum of its proper divisors (39344075463).

81667213497 is a wasteful number, since it uses less digits than its factorization.

81667213497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 570621 (or 570615 counting only the distinct ones).

The product of its digits is 3048192, while the sum is 54.

The spelling of 81667213497 in words is "eighty-one billion, six hundred sixty-seven million, two hundred thirteen thousand, four hundred ninety-seven".