81197552990 has 16 divisors (see below), whose sum is σ = 146190037248. Its totient is φ = 32471367456.

The previous prime is 81197552959. The next prime is 81197553029. The reversal of 81197552990 is 9925579118.

It is a super-2 number, since 2×81197552990² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 912062 + ... + 997121.

It is an arithmetic number, because the mean of its divisors is an integer number (9136877328).

Almost surely, 2^81197552990 is an apocalyptic number.

81197552990 is a deficient number, since it is larger than the sum of its proper divisors (64992484258).

81197552990 is a wasteful number, since it uses less digits than its factorization.

81197552990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1913443.

The product of its (nonzero) digits is 2041200, while the sum is 56.

The spelling of 81197552990 in words is "eighty-one billion, one hundred ninety-seven million, five hundred fifty-two thousand, nine hundred ninety".