81697156 has 12 divisors (see below), whose sum is σ = 143034892. Its totient is φ = 40830048.

The previous prime is 81697153. The next prime is 81697163. The reversal of 81697156 is 65179618.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 22714756 + 58982400 = 4766^2 + 7680^2 .

It is not an unprimeable number, because it can be changed into a prime (81697151) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 11626 + ... + 17278.

Almost surely, 2^81697156 is an apocalyptic number.

It is an amenable number.

81697156 is a deficient number, since it is larger than the sum of its proper divisors (61337736).

81697156 is a wasteful number, since it uses less digits than its factorization.

81697156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9270 (or 9268 counting only the distinct ones).

The product of its digits is 90720, while the sum is 43.

The square root of 81697156 is about 9038.6479077349. The cubic root of 81697156 is about 433.9126513387.

The spelling of 81697156 in words is "eighty-one million, six hundred ninety-seven thousand, one hundred fifty-six".