81926284977 has 10 divisors (see below), whose sum is σ = 122383709778. Its totient is φ = 54617523264.

The previous prime is 81926284969. The next prime is 81926285017. The reversal of 81926284977 is 77948262918.

81926284977 is a `hidden beast` number, since 81 + 9 + 2 + 62 + 8 + 497 + 7 = 666.

It can be written as a sum of positive squares in only one way, i.e., 74384925696 + 7541359281 = 272736^2 + 86841^2 .

It is not a de Polignac number, because 81926284977 - 2³ = 81926284969 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81926284907) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 505717728 + ... + 505717889.

Almost surely, 2^81926284977 is an apocalyptic number.

It is an amenable number.

81926284977 is a deficient number, since it is larger than the sum of its proper divisors (40457424801).

81926284977 is a wasteful number, since it uses less digits than its factorization.

81926284977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1011435629 (or 1011435620 counting only the distinct ones).

The product of its digits is 24385536, while the sum is 63.

The spelling of 81926284977 in words is "eighty-one billion, nine hundred twenty-six million, two hundred eighty-four thousand, nine hundred seventy-seven".