81697611 has 16 divisors (see below), whose sum is σ = 113218560. Its totient is φ = 52338720.

The previous prime is 81697607. The next prime is 81697657. The reversal of 81697611 is 11679618.

It is not a de Polignac number, because 81697611 - 2² = 81697607 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81697611.

It is not an unprimeable number, because it can be changed into a prime (81697601) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17296 + ... + 21506.

It is an arithmetic number, because the mean of its divisors is an integer number (7076160).

Almost surely, 2^81697611 is an apocalyptic number.

81697611 is a deficient number, since it is larger than the sum of its proper divisors (31520949).

81697611 is a wasteful number, since it uses less digits than its factorization.

81697611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4466.

The product of its digits is 18144, while the sum is 39.

The square root of 81697611 is about 9038.6730773936. The cubic root of 81697611 is about 433.9134568743.

The spelling of 81697611 in words is "eighty-one million, six hundred ninety-seven thousand, six hundred eleven".