81070999 has 4 divisors (see below), whose sum is σ = 81247320. Its totient is φ = 80894680.

The previous prime is 81070963. The next prime is 81071009. The reversal of 81070999 is 99907018.

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 81070999 - 2¹⁵ = 81038231 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81070919) 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, 87469 + ... + 88390.

It is an arithmetic number, because the mean of its divisors is an integer number (20311830).

Almost surely, 2^81070999 is an apocalyptic number.

81070999 is a deficient number, since it is larger than the sum of its proper divisors (176321).

81070999 is a wasteful number, since it uses less digits than its factorization.

81070999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176320.

The product of its (nonzero) digits is 40824, while the sum is 43.

The square root of 81070999 is about 9003.9435249228. The cubic root of 81070999 is about 432.8012518001.

The spelling of 81070999 in words is "eighty-one million, seventy thousand, nine hundred ninety-nine".