81677177064 has 256 divisors, whose sum is σ = 267535564800. Its totient is φ = 22600353024.

The previous prime is 81677177051. The next prime is 81677177077. The reversal of 81677177064 is 46077177618.

It is an interprime number because it is at equal distance from previous prime (81677177051) and next prime (81677177077).

It is a super-2 number, since 2×81677177064² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 81677177064.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 12472239 + ... + 12478785.

It is an arithmetic number, because the mean of its divisors is an integer number (1045060800).

Almost surely, 2^81677177064 is an apocalyptic number.

81677177064 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81677177064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133767782400).

81677177064 is an abundant number, since it is smaller than the sum of its proper divisors (185858387736).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81677177064 is a wasteful number, since it uses less digits than its factorization.

81677177064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6829 (or 6819 counting only the distinct ones).

The product of its (nonzero) digits is 2765952, while the sum is 54.

The spelling of 81677177064 in words is "eighty-one billion, six hundred seventy-seven million, one hundred seventy-seven thousand, sixty-four".