81613259 has 16 divisors (see below), whose sum is σ = 100703232. Its totient is φ = 64408608.

The previous prime is 81613219. The next prime is 81613261. The reversal of 81613259 is 95231618.

It is a cyclic number.

It is not a de Polignac number, because 81613259 - 2¹⁶ = 81547723 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81613219) 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, 44882 + ... + 46664.

It is an arithmetic number, because the mean of its divisors is an integer number (6293952).

Almost surely, 2^81613259 is an apocalyptic number.

81613259 is a deficient number, since it is larger than the sum of its proper divisors (19089973).

81613259 is a wasteful number, since it uses less digits than its factorization.

81613259 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2306.

The product of its digits is 12960, while the sum is 35.

The square root of 81613259 is about 9034.0057006845. The cubic root of 81613259 is about 433.7640682872.

The spelling of 81613259 in words is "eighty-one million, six hundred thirteen thousand, two hundred fifty-nine".