81085690 has 48 divisors (see below), whose sum is σ = 171251712. Its totient is φ = 27560736.

The previous prime is 81085663. The next prime is 81085709. The reversal of 81085690 is 9658018.

It is a super-2 number, since 2×81085690² = 13149778245552200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 61579 + ... + 62881.

It is an arithmetic number, because the mean of its divisors is an integer number (3567744).

Almost surely, 2^81085690 is an apocalyptic number.

81085690 is an abundant number, since it is smaller than the sum of its proper divisors (90166022).

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

81085690 is a wasteful number, since it uses less digits than its factorization.

81085690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1451 (or 1444 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 37.

The square root of 81085690 is about 9004.7592971717. The cubic root of 81085690 is about 432.8273930806.

The spelling of 81085690 in words is "eighty-one million, eighty-five thousand, six hundred ninety".