81719844869 has 8 divisors (see below), whose sum is σ = 88042950912. Its totient is φ = 75402019440.

The previous prime is 81719844851. The next prime is 81719844971. The reversal of 81719844869 is 96844891718.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81719844869 - 2³² = 77424877573 is a prime.

It is a super-2 number, since 2×81719844869² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81719844839) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1287977 + ... + 1349934.

It is an arithmetic number, because the mean of its divisors is an integer number (11005368864).

Almost surely, 2^81719844869 is an apocalyptic number.

It is an amenable number.

81719844869 is a deficient number, since it is larger than the sum of its proper divisors (6323106043).

81719844869 is a wasteful number, since it uses less digits than its factorization.

81719844869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2640307.

The product of its digits is 27869184, while the sum is 65.

The spelling of 81719844869 in words is "eighty-one billion, seven hundred nineteen million, eight hundred forty-four thousand, eight hundred sixty-nine".