81111690 has 48 divisors (see below), whose sum is σ = 230065056. Its totient is φ = 19663200.

The previous prime is 81111689. The next prime is 81111721. The reversal of 81111690 is 9611118.

It is a super-2 number, since 2×81111690² = 13158212509312200, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 39976 + ... + 41955.

It is an arithmetic number, because the mean of its divisors is an integer number (4793022).

Almost surely, 2^81111690 is an apocalyptic number.

81111690 is an abundant number, since it is smaller than the sum of its proper divisors (148953366).

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

81111690 is a wasteful number, since it uses less digits than its factorization.

81111690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81955 (or 81952 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 27.

The square root of 81111690 is about 9006.2028624721. The cubic root of 81111690 is about 432.8736499463.

It can be divided in two parts, 8111 and 1690, that added together give a square (9801 = 99²).

The spelling of 81111690 in words is "eighty-one million, one hundred eleven thousand, six hundred ninety".