81307601 has 2 divisors, whose sum is σ = 81307602. Its totient is φ = 81307600.

The previous prime is 81307591. The next prime is 81307607. The reversal of 81307601 is 10670318.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57532225 + 23775376 = 7585^2 + 4876^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81307601 is a prime.

It is a super-2 number, since 2×81307601² = 13221851960750402, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81307607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40653800 + 40653801.

It is an arithmetic number, because the mean of its divisors is an integer number (40653801).

Almost surely, 2^81307601 is an apocalyptic number.

It is an amenable number.

81307601 is a deficient number, since it is larger than the sum of its proper divisors (1).

81307601 is an equidigital number, since it uses as much as digits as its factorization.

81307601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 81307601 is about 9017.0727511760. The cubic root of 81307601 is about 433.2218797520.

Adding to 81307601 its reverse (10670318), we get a palindrome (91977919).

The spelling of 81307601 in words is "eighty-one million, three hundred seven thousand, six hundred one".