81308769 has 8 divisors (see below), whose sum is σ = 108466752. Its totient is φ = 54178320.

The previous prime is 81308761. The next prime is 81308783. The reversal of 81308769 is 96780318.

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

It is not a de Polignac number, because 81308769 - 2³ = 81308761 is a prime.

It is a super-2 number, since 2×81308769² = 13222231832590722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81308769.

It is not an unprimeable number, because it can be changed into a prime (81308761) 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, 1452 + ... + 12834.

It is an arithmetic number, because the mean of its divisors is an integer number (13558344).

Almost surely, 2^81308769 is an apocalyptic number.

It is an amenable number.

81308769 is a deficient number, since it is larger than the sum of its proper divisors (27157983).

81308769 is a wasteful number, since it uses less digits than its factorization.

81308769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13767.

The product of its (nonzero) digits is 72576, while the sum is 42.

The square root of 81308769 is about 9017.1375169729. The cubic root of 81308769 is about 433.2239541819.

The spelling of 81308769 in words is "eighty-one million, three hundred eight thousand, seven hundred sixty-nine".