81697960 has 16 divisors (see below), whose sum is σ = 183820500. Its totient is φ = 32679168.

The previous prime is 81697939. The next prime is 81697969. The reversal of 81697960 is 6979618.

It can be written as a sum of positive squares in 2 ways, for example, as 79245604 + 2452356 = 8902^2 + 1566^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81697960.

It is not an unprimeable number, because it can be changed into a prime (81697969) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1021185 + ... + 1021264.

Almost surely, 2^81697960 is an apocalyptic number.

It is an amenable number.

81697960 is an abundant number, since it is smaller than the sum of its proper divisors (102122540).

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

81697960 is a wasteful number, since it uses less digits than its factorization.

81697960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2042460 (or 2042456 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 46.

The square root of 81697960 is about 9038.6923833041. The cubic root of 81697960 is about 433.9140747446.

It can be divided in two parts, 8169 and 7960, that added together give a square (16129 = 127²).

The spelling of 81697960 in words is "eighty-one million, six hundred ninety-seven thousand, nine hundred sixty".