81881707 has 8 divisors (see below), whose sum is σ = 86834592. Its totient is φ = 76944000.

The previous prime is 81881699. The next prime is 81881711. The reversal of 81881707 is 70718818.

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

It is a cyclic number.

It is not a de Polignac number, because 81881707 - 2³ = 81881699 is a prime.

It is a super-2 number, since 2×81881707² = 13409227882467698, which contains 22 as substring.

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 81881707.

It is not an unprimeable number, because it can be changed into a prime (81881747) 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, 8482 + ... + 15352.

It is an arithmetic number, because the mean of its divisors is an integer number (10854324).

Almost surely, 2^81881707 is an apocalyptic number.

81881707 is a deficient number, since it is larger than the sum of its proper divisors (4952885).

81881707 is a wasteful number, since it uses less digits than its factorization.

81881707 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7589.

The product of its (nonzero) digits is 25088, while the sum is 40.

The square root of 81881707 is about 9048.8511425484. The cubic root of 81881707 is about 434.2391367581.

The spelling of 81881707 in words is "eighty-one million, eight hundred eighty-one thousand, seven hundred seven".