81687291830 has 32 divisors (see below), whose sum is σ = 154352839680. Its totient is φ = 31084932960.

The previous prime is 81687291779. The next prime is 81687291841. The reversal of 81687291830 is 3819278618.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2214824 + ... + 2251403.

It is an arithmetic number, because the mean of its divisors is an integer number (4823526240).

Almost surely, 2^81687291830 is an apocalyptic number.

81687291830 is a deficient number, since it is larger than the sum of its proper divisors (72665547850).

81687291830 is a wasteful number, since it uses less digits than its factorization.

81687291830 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4466324.

The product of its (nonzero) digits is 1161216, while the sum is 53.

The spelling of 81687291830 in words is "eighty-one billion, six hundred eighty-seven million, two hundred ninety-one thousand, eight hundred thirty".