81891962810 has 32 divisors (see below), whose sum is σ = 168536011392. Its totient is φ = 28065153600.

The previous prime is 81891962791. The next prime is 81891962839. The reversal of 81891962810 is 1826919818.

It is a happy number.

It is a super-2 number, since 2×81891962810² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87416 + ... + 414035.

It is an arithmetic number, because the mean of its divisors is an integer number (5266750356).

Almost surely, 2^81891962810 is an apocalyptic number.

81891962810 is an abundant number, since it is smaller than the sum of its proper divisors (86644048582).

81891962810 is a wasteful number, since it uses less digits than its factorization.

81891962810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 503798.

The product of its (nonzero) digits is 497664, while the sum is 53.

The spelling of 81891962810 in words is "eighty-one billion, eight hundred ninety-one million, nine hundred sixty-two thousand, eight hundred ten".