81701569 has 2 divisors, whose sum is σ = 81701570. Its totient is φ = 81701568.

The previous prime is 81701551. The next prime is 81701573. The reversal of 81701569 is 96510718.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 74166544 + 7535025 = 8612^2 + 2745^2 .

It is a cyclic number.

It is not a de Polignac number, because 81701569 - 2⁵ = 81701537 is a prime.

It is a super-2 number, since 2×81701569² = 13350292754123522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81701519) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40850784 + 40850785.

It is an arithmetic number, because the mean of its divisors is an integer number (40850785).

Almost surely, 2^81701569 is an apocalyptic number.

It is an amenable number.

81701569 is a deficient number, since it is larger than the sum of its proper divisors (1).

81701569 is an equidigital number, since it uses as much as digits as its factorization.

81701569 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15120, while the sum is 37.

The square root of 81701569 is about 9038.8920228090. The cubic root of 81701569 is about 433.9204640222.

The spelling of 81701569 in words is "eighty-one million, seven hundred one thousand, five hundred sixty-nine".