81706497 has 4 divisors (see below), whose sum is σ = 108942000. Its totient is φ = 54470996.

The previous prime is 81706489. The next prime is 81706507. The reversal of 81706497 is 79460718.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81706497 - 2³ = 81706489 is a prime.

It is a super-2 number, since 2×81706497² = 13351903304022018, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81706447) 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, 13617747 + ... + 13617752.

It is an arithmetic number, because the mean of its divisors is an integer number (27235500).

Almost surely, 2^81706497 is an apocalyptic number.

It is an amenable number.

81706497 is a deficient number, since it is larger than the sum of its proper divisors (27235503).

81706497 is a wasteful number, since it uses less digits than its factorization.

81706497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27235502.

The product of its (nonzero) digits is 84672, while the sum is 42.

The square root of 81706497 is about 9039.1646184811. The cubic root of 81706497 is about 433.9291881184.

The spelling of 81706497 in words is "eighty-one million, seven hundred six thousand, four hundred ninety-seven".