81727615715 has 4 divisors (see below), whose sum is σ = 98073138864. Its totient is φ = 65382092568.

The previous prime is 81727615693. The next prime is 81727615729. The reversal of 81727615715 is 51751672718.

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

It is a cyclic number.

It is not a de Polignac number, because 81727615715 - 2¹⁸ = 81727353571 is a prime.

It is a super-2 number, since 2×81727615715² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8172761567 + ... + 8172761576.

It is an arithmetic number, because the mean of its divisors is an integer number (24518284716).

Almost surely, 2^81727615715 is an apocalyptic number.

81727615715 is a deficient number, since it is larger than the sum of its proper divisors (16345523149).

81727615715 is a wasteful number, since it uses less digits than its factorization.

81727615715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16345523148.

The product of its digits is 823200, while the sum is 50.

The spelling of 81727615715 in words is "eighty-one billion, seven hundred twenty-seven million, six hundred fifteen thousand, seven hundred fifteen".