81349687815 has 64 divisors (see below), whose sum is σ = 147463759872. Its totient is φ = 37949788800.

The previous prime is 81349687813. The next prime is 81349687817. The reversal of 81349687815 is 51878694318.

It is an interprime number because it is at equal distance from previous prime (81349687813) and next prime (81349687817).

It is not a de Polignac number, because 81349687815 - 2¹ = 81349687813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81349687813) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 389800 + ... + 560930.

It is an arithmetic number, because the mean of its divisors is an integer number (2304121248).

Almost surely, 2^81349687815 is an apocalyptic number.

81349687815 is a deficient number, since it is larger than the sum of its proper divisors (66114072057).

81349687815 is a wasteful number, since it uses less digits than its factorization.

81349687815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171260.

The product of its digits is 11612160, while the sum is 60.

The spelling of 81349687815 in words is "eighty-one billion, three hundred forty-nine million, six hundred eighty-seven thousand, eight hundred fifteen".