81373977658 has 8 divisors (see below), whose sum is σ = 122247891828. Its totient is φ = 40624680384.

The previous prime is 81373977653. The next prime is 81373977661. The reversal of 81373977658 is 85677937318.

It can be written as a sum of positive squares in 2 ways, for example, as 78788560249 + 2585417409 = 280693^2 + 50847^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 81373977658.

It is not an unprimeable number, because it can be changed into a prime (81373977653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31152591 + ... + 31155202.

Almost surely, 2^81373977658 is an apocalyptic number.

81373977658 is a deficient number, since it is larger than the sum of its proper divisors (40873914170).

81373977658 is a wasteful number, since it uses less digits than its factorization.

81373977658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62308448.

The product of its digits is 53343360, while the sum is 64.

The spelling of 81373977658 in words is "eighty-one billion, three hundred seventy-three million, nine hundred seventy-seven thousand, six hundred fifty-eight".