81613015 has 16 divisors (see below), whose sum is σ = 107185536. Its totient is φ = 59162400.

The previous prime is 81613013. The next prime is 81613019. The reversal of 81613015 is 51031618.

It is not a de Polignac number, because 81613015 - 2¹ = 81613013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81613013) 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, 15964 + ... + 20446.

It is an arithmetic number, because the mean of its divisors is an integer number (6699096).

Almost surely, 2^81613015 is an apocalyptic number.

81613015 is a deficient number, since it is larger than the sum of its proper divisors (25572521).

81613015 is a wasteful number, since it uses less digits than its factorization.

81613015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4830.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 81613015 is about 9033.9921961445. The cubic root of 81613015 is about 433.7636360105.

It can be divided in two parts, 816 and 13015, that added together give a palindrome (13831).

The spelling of 81613015 in words is "eighty-one million, six hundred thirteen thousand, fifteen".