81536986 has 4 divisors (see below), whose sum is σ = 122305482. Its totient is φ = 40768492.

The previous prime is 81536977. The next prime is 81536993. The reversal of 81536986 is 68963518.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 77105961 + 4431025 = 8781^2 + 2105^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20384245 + ... + 20384248.

Almost surely, 2^81536986 is an apocalyptic number.

81536986 is a deficient number, since it is larger than the sum of its proper divisors (40768496).

81536986 is a wasteful number, since it uses less digits than its factorization.

81536986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40768495.

The product of its digits is 311040, while the sum is 46.

The square root of 81536986 is about 9029.7832753616. The cubic root of 81536986 is about 433.6288990794.

The spelling of 81536986 in words is "eighty-one million, five hundred thirty-six thousand, nine hundred eighty-six".