81577907 has 2 divisors, whose sum is σ = 81577908. Its totient is φ = 81577906.

The previous prime is 81577879. The next prime is 81577919. The reversal of 81577907 is 70977518.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81577907 - 2¹⁴ = 81561523 is a prime.

It is not a weakly prime, because it can be changed into another prime (81577607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40788953 + 40788954.

It is an arithmetic number, because the mean of its divisors is an integer number (40788954).

Almost surely, 2^81577907 is an apocalyptic number.

81577907 is a deficient number, since it is larger than the sum of its proper divisors (1).

81577907 is an equidigital number, since it uses as much as digits as its factorization.

81577907 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 123480, while the sum is 44.

The square root of 81577907 is about 9032.0488816215. The cubic root of 81577907 is about 433.7014287840.

The spelling of 81577907 in words is "eighty-one million, five hundred seventy-seven thousand, nine hundred seven".