81995299 has 4 divisors (see below), whose sum is σ = 85560336. Its totient is φ = 78430264.

The previous prime is 81995297. The next prime is 81995311. The reversal of 81995299 is 99259918.

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 81995299 - 2¹ = 81995297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81995297) 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, 1782484 + ... + 1782529.

It is an arithmetic number, because the mean of its divisors is an integer number (21390084).

Almost surely, 2^81995299 is an apocalyptic number.

81995299 is a deficient number, since it is larger than the sum of its proper divisors (3565037).

81995299 is a wasteful number, since it uses less digits than its factorization.

81995299 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3565036.

The product of its digits is 524880, while the sum is 52.

The square root of 81995299 is about 9055.1255651150. The cubic root of 81995299 is about 434.4398462200.

The spelling of 81995299 in words is "eighty-one million, nine hundred ninety-five thousand, two hundred ninety-nine".