81086690 has 16 divisors (see below), whose sum is σ = 148349880. Its totient is φ = 31902720.

The previous prime is 81086641. The next prime is 81086711. The reversal of 81086690 is 9668018.

It can be written as a sum of positive squares in 4 ways, for example, as 52432081 + 28654609 = 7241^2 + 5353^2 .

It is a super-2 number, since 2×81086690² = 13150102590312200, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 65855 + ... + 67074.

Almost surely, 2^81086690 is an apocalyptic number.

81086690 is a deficient number, since it is larger than the sum of its proper divisors (67263190).

81086690 is a wasteful number, since it uses less digits than its factorization.

81086690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132997.

The product of its (nonzero) digits is 20736, while the sum is 38.

The square root of 81086690 is about 9004.8148231932. The cubic root of 81086690 is about 432.8291723736.

The spelling of 81086690 in words is "eighty-one million, eighty-six thousand, six hundred ninety".