81310664602 has 16 divisors (see below), whose sum is σ = 122331093192. Its totient is φ = 40533779520.

The previous prime is 81310664527. The next prime is 81310664623. The reversal of 81310664602 is 20646601318.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 81213030441 + 97634161 = 284979^2 + 9881^2 .

It is a super-2 number, since 2×81310664602² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1104868 + ... + 1176160.

Almost surely, 2^81310664602 is an apocalyptic number.

81310664602 is a deficient number, since it is larger than the sum of its proper divisors (41020428590).

81310664602 is a wasteful number, since it uses less digits than its factorization.

81310664602 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72993.

The product of its (nonzero) digits is 41472, while the sum is 37.

The spelling of 81310664602 in words is "eighty-one billion, three hundred ten million, six hundred sixty-four thousand, six hundred two".