81390594264 has 192 divisors, whose sum is σ = 245176243200. Its totient is φ = 22423516416.

The previous prime is 81390594169. The next prime is 81390594269. The reversal of 81390594264 is 46249509318.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81390594269) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 51939609 + ... + 51941175.

It is an arithmetic number, because the mean of its divisors is an integer number (1276959600).

Almost surely, 2^81390594264 is an apocalyptic number.

81390594264 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 81390594264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122588121600).

81390594264 is an abundant number, since it is smaller than the sum of its proper divisors (163785648936).

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

81390594264 is a wasteful number, since it uses less digits than its factorization.

81390594264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3142 (or 3131 counting only the distinct ones).

The product of its (nonzero) digits is 1866240, while the sum is 51.

The spelling of 81390594264 in words is "eighty-one billion, three hundred ninety million, five hundred ninety-four thousand, two hundred sixty-four".