81177509390 has 64 divisors (see below), whose sum is σ = 155355494400. Its totient is φ = 30476818944.

The previous prime is 81177509359. The next prime is 81177509411. The reversal of 81177509390 is 9390577118.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2948006 + ... + 2975414.

It is an arithmetic number, because the mean of its divisors is an integer number (2427429600).

Almost surely, 2^81177509390 is an apocalyptic number.

81177509390 is a deficient number, since it is larger than the sum of its proper divisors (74177985010).

81177509390 is a wasteful number, since it uses less digits than its factorization.

81177509390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27681.

The product of its (nonzero) digits is 476280, while the sum is 50.

The spelling of 81177509390 in words is "eighty-one billion, one hundred seventy-seven million, five hundred nine thousand, three hundred ninety".