81363687990 has 64 divisors (see below), whose sum is σ = 211584151296. Its totient is φ = 19905098112.

The previous prime is 81363687961. The next prime is 81363687991. The reversal of 81363687990 is 9978636318.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81363687991) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 576384 + ... + 703523.

It is an arithmetic number, because the mean of its divisors is an integer number (3306002364).

Almost surely, 2^81363687990 is an apocalyptic number.

81363687990 is an abundant number, since it is smaller than the sum of its proper divisors (130220463306).

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

81363687990 is a wasteful number, since it uses less digits than its factorization.

81363687990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1280093.

The product of its (nonzero) digits is 11757312, while the sum is 60.

The spelling of 81363687990 in words is "eighty-one billion, three hundred sixty-three million, six hundred eighty-seven thousand, nine hundred ninety".