81613767 has 4 divisors (see below), whose sum is σ = 108818360. Its totient is φ = 54409176.

The previous prime is 81613733. The next prime is 81613769. The reversal of 81613767 is 76731618.

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

It is not a de Polignac number, because 81613767 - 2⁶ = 81613703 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 (81613769) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13602292 + ... + 13602297.

It is an arithmetic number, because the mean of its divisors is an integer number (27204590).

Almost surely, 2^81613767 is an apocalyptic number.

81613767 is a deficient number, since it is larger than the sum of its proper divisors (27204593).

81613767 is a wasteful number, since it uses less digits than its factorization.

81613767 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27204592.

The product of its digits is 42336, while the sum is 39.

The square root of 81613767 is about 9034.0338166292. The cubic root of 81613767 is about 433.7649682704.

The spelling of 81613767 in words is "eighty-one million, six hundred thirteen thousand, seven hundred sixty-seven".