81682613 has 4 divisors (see below), whose sum is σ = 84317568. Its totient is φ = 79047660.

The previous prime is 81682607. The next prime is 81682631. The reversal of 81682613 is 31628618.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81682613 - 2⁴ = 81682597 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 (81682813) 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, 1317431 + ... + 1317492.

It is an arithmetic number, because the mean of its divisors is an integer number (21079392).

Almost surely, 2^81682613 is an apocalyptic number.

It is an amenable number.

81682613 is a deficient number, since it is larger than the sum of its proper divisors (2634955).

81682613 is a wasteful number, since it uses less digits than its factorization.

81682613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2634954.

The product of its digits is 13824, while the sum is 35.

The square root of 81682613 is about 9037.8433821349. The cubic root of 81682613 is about 433.8869027225.

The spelling of 81682613 in words is "eighty-one million, six hundred eighty-two thousand, six hundred thirteen".