81976072 has 8 divisors (see below), whose sum is σ = 153705150. Its totient is φ = 40988032.

The previous prime is 81976039. The next prime is 81976073. The reversal of 81976072 is 27067918.

It can be written as a sum of positive squares in only one way, i.e., 81974916 + 1156 = 9054^2 + 34^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (81976073) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5123497 + ... + 5123512.

Almost surely, 2^81976072 is an apocalyptic number.

It is an amenable number.

81976072 is a deficient number, since it is larger than the sum of its proper divisors (71729078).

81976072 is a wasteful number, since it uses less digits than its factorization.

81976072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10247015 (or 10247011 counting only the distinct ones).

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 81976072 is about 9054.0638389620. The cubic root of 81976072 is about 434.4058864362.

It can be divided in two parts, 8 and 1976072, that multiplied together give a square (15808576 = 3976²).

The spelling of 81976072 in words is "eighty-one million, nine hundred seventy-six thousand, seventy-two".