81151699 has 4 divisors (see below), whose sum is σ = 81896320. Its totient is φ = 80407080.

The previous prime is 81151667. The next prime is 81151709. The reversal of 81151699 is 99615118.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81151699 - 2⁵ = 81151667 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81161699) 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, 372147 + ... + 372364.

It is an arithmetic number, because the mean of its divisors is an integer number (20474080).

Almost surely, 2^81151699 is an apocalyptic number.

81151699 is a deficient number, since it is larger than the sum of its proper divisors (744621).

81151699 is a wasteful number, since it uses less digits than its factorization.

81151699 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 744620.

The product of its digits is 19440, while the sum is 40.

The square root of 81151699 is about 9008.4237799961. The cubic root of 81151699 is about 432.9448110621.

The spelling of 81151699 in words is "eighty-one million, one hundred fifty-one thousand, six hundred ninety-nine".