81140345990 has 64 divisors (see below), whose sum is σ = 168261069312. Its totient is φ = 27882624000.

The previous prime is 81140345981. The next prime is 81140346011. The reversal of 81140345990 is 9954304118.

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, 16790 + ... + 403190.

It is an arithmetic number, because the mean of its divisors is an integer number (2629079208).

Almost surely, 2^81140345990 is an apocalyptic number.

81140345990 is an abundant number, since it is smaller than the sum of its proper divisors (87120723322).

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

81140345990 is a wasteful number, since it uses less digits than its factorization.

81140345990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 386525.

The product of its (nonzero) digits is 155520, while the sum is 44.

The spelling of 81140345990 in words is "eighty-one billion, one hundred forty million, three hundred forty-five thousand, nine hundred ninety".