81376613 has 2 divisors, whose sum is σ = 81376614. Its totient is φ = 81376612.

The previous prime is 81376591. The next prime is 81376621. The reversal of 81376613 is 31667318.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43652449 + 37724164 = 6607^2 + 6142^2 .

It is a cyclic number.

It is not a de Polignac number, because 81376613 - 2¹² = 81372517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81376313) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40688306 + 40688307.

It is an arithmetic number, because the mean of its divisors is an integer number (40688307).

Almost surely, 2^81376613 is an apocalyptic number.

It is an amenable number.

81376613 is a deficient number, since it is larger than the sum of its proper divisors (1).

81376613 is an equidigital number, since it uses as much as digits as its factorization.

81376613 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18144, while the sum is 35.

The square root of 81376613 is about 9020.8986802868. The cubic root of 81376613 is about 433.3444146410.

The spelling of 81376613 in words is "eighty-one million, three hundred seventy-six thousand, six hundred thirteen".