81719031 has 4 divisors (see below), whose sum is σ = 108958712. Its totient is φ = 54479352.

The previous prime is 81719021. The next prime is 81719063. The reversal of 81719031 is 13091718.

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

It is not a de Polignac number, because 81719031 - 2⁹ = 81718519 is a prime.

It is a super-2 number, since 2×81719031² = 13356000055157922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81719031.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81719021) 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, 13619836 + ... + 13619841.

It is an arithmetic number, because the mean of its divisors is an integer number (27239678).

Almost surely, 2^81719031 is an apocalyptic number.

81719031 is a deficient number, since it is larger than the sum of its proper divisors (27239681).

81719031 is a wasteful number, since it uses less digits than its factorization.

81719031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27239680.

The product of its (nonzero) digits is 1512, while the sum is 30.

The square root of 81719031 is about 9039.8579081753. The cubic root of 81719031 is about 433.9513756252.

The spelling of 81719031 in words is "eighty-one million, seven hundred nineteen thousand, thirty-one".