81072679 has 4 divisors (see below), whose sum is σ = 81114480. Its totient is φ = 81030880.

The previous prime is 81072671. The next prime is 81072709. The reversal of 81072679 is 97627018.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97627018 = 2 ⋅48813509.

It is a cyclic number.

It is not a de Polignac number, because 81072679 - 2³ = 81072671 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81072671) 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, 17842 + ... + 21919.

It is an arithmetic number, because the mean of its divisors is an integer number (20278620).

Almost surely, 2^81072679 is an apocalyptic number.

81072679 is a deficient number, since it is larger than the sum of its proper divisors (41801).

81072679 is a wasteful number, since it uses less digits than its factorization.

81072679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41800.

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 81072679 is about 9004.0368168950. The cubic root of 81072679 is about 432.8042413652.

The spelling of 81072679 in words is "eighty-one million, seventy-two thousand, six hundred seventy-nine".