811861515817 has 16 divisors (see below), whose sum is σ = 894333847680. Its totient is φ = 730834732800.

The previous prime is 811861515769. The next prime is 811861515821. The reversal of 811861515817 is 718515168118.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-811861515817 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (811861515617) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25055967 + ... + 25088347.

It is an arithmetic number, because the mean of its divisors is an integer number (55895865480).

Almost surely, 2^811861515817 is an apocalyptic number.

It is an amenable number.

811861515817 is a deficient number, since it is larger than the sum of its proper divisors (82472331863).

811861515817 is a wasteful number, since it uses less digits than its factorization.

811861515817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54624.

The product of its digits is 537600, while the sum is 52.

The spelling of 811861515817 in words is "eight hundred eleven billion, eight hundred sixty-one million, five hundred fifteen thousand, eight hundred seventeen".