81376861 has 2 divisors, whose sum is σ = 81376862. Its totient is φ = 81376860.

The previous prime is 81376843. The next prime is 81376877. The reversal of 81376861 is 16867318.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55428025 + 25948836 = 7445^2 + 5094^2 .

It is a cyclic number.

It is not a de Polignac number, because 81376861 - 2¹³ = 81368669 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81373861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40688430 + 40688431.

It is an arithmetic number, because the mean of its divisors is an integer number (40688431).

Almost surely, 2^81376861 is an apocalyptic number.

It is an amenable number.

81376861 is a deficient number, since it is larger than the sum of its proper divisors (1).

81376861 is an equidigital number, since it uses as much as digits as its factorization.

81376861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 40.

The square root of 81376861 is about 9020.9124261352. The cubic root of 81376861 is about 433.3448548547.

The spelling of 81376861 in words is "eighty-one million, three hundred seventy-six thousand, eight hundred sixty-one".