81706457 has 8 divisors (see below), whose sum is σ = 93517632. Its totient is φ = 69930000.

The previous prime is 81706447. The next prime is 81706463. The reversal of 81706457 is 75460718.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81706457 - 2⁶ = 81706393 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81706457.

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 7 ways as a sum of consecutive naturals, for example, 3419 + ... + 13232.

It is an arithmetic number, because the mean of its divisors is an integer number (11689704).

Almost surely, 2^81706457 is an apocalyptic number.

It is an amenable number.

81706457 is a deficient number, since it is larger than the sum of its proper divisors (11811175).

81706457 is a wasteful number, since it uses less digits than its factorization.

81706457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17359.

The product of its (nonzero) digits is 47040, while the sum is 38.

The square root of 81706457 is about 9039.1624058870. The cubic root of 81706457 is about 433.9291173074.

The spelling of 81706457 in words is "eighty-one million, seven hundred six thousand, four hundred fifty-seven".