81685701 has 12 divisors (see below), whose sum is σ = 118251328. Its totient is φ = 54336744.

The previous prime is 81685699. The next prime is 81685727. The reversal of 81685701 is 10758618.

81685701 is a `hidden beast` number, since 81 + 6 + 8 + 570 + 1 = 666.

It is not a de Polignac number, because 81685701 - 2¹ = 81685699 is a prime.

It is a super-2 number, since 2×81685701² = 13345107495722802, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81685781) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5635 + ... + 13968.

Almost surely, 2^81685701 is an apocalyptic number.

It is an amenable number.

81685701 is a deficient number, since it is larger than the sum of its proper divisors (36565627).

81685701 is a wasteful number, since it uses less digits than its factorization.

81685701 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20072 (or 20069 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 36.

The square root of 81685701 is about 9038.0142177361. The cubic root of 81685701 is about 433.8923703319.

The spelling of 81685701 in words is "eighty-one million, six hundred eighty-five thousand, seven hundred one".