81637672 has 32 divisors (see below), whose sum is σ = 169128000. Its totient is φ = 36745984.

The previous prime is 81637669. The next prime is 81637681. The reversal of 81637672 is 27673618.

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 7 ways as a sum of consecutive naturals, for example, 9922 + ... + 16177.

It is an arithmetic number, because the mean of its divisors is an integer number (5285250).

Almost surely, 2^81637672 is an apocalyptic number.

It is an amenable number.

81637672 is an abundant number, since it is smaller than the sum of its proper divisors (87490328).

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

81637672 is a wasteful number, since it uses less digits than its factorization.

81637672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26145 (or 26141 counting only the distinct ones).

The product of its digits is 84672, while the sum is 40.

The square root of 81637672 is about 9035.3567721480. The cubic root of 81637672 is about 433.8073146364.

The spelling of 81637672 in words is "eighty-one million, six hundred thirty-seven thousand, six hundred seventy-two".