81199592390 has 32 divisors (see below), whose sum is σ = 172427526144. Its totient is φ = 26941799520.

The previous prime is 81199592351. The next prime is 81199592429. The reversal of 81199592390 is 9329599118.

It is an interprime number because it is at equal distance from previous prime (81199592351) and next prime (81199592429).

It is a Smith number, since the sum of its digits (56) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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, 18707414 + ... + 18711753.

It is an arithmetic number, because the mean of its divisors is an integer number (5388360192).

Almost surely, 2^81199592390 is an apocalyptic number.

81199592390 is an abundant number, since it is smaller than the sum of its proper divisors (91227933754).

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

81199592390 is a wasteful number, since it uses less digits than its factorization.

81199592390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37419212.

The product of its (nonzero) digits is 1574640, while the sum is 56.

The spelling of 81199592390 in words is "eighty-one billion, one hundred ninety-nine million, five hundred ninety-two thousand, three hundred ninety".