81256801 has 2 divisors, whose sum is σ = 81256802. Its totient is φ = 81256800.

The previous prime is 81256781. The next prime is 81256817. The reversal of 81256801 is 10865218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 74805201 + 6451600 = 8649^2 + 2540^2 .

It is a cyclic number.

It is not a de Polignac number, because 81256801 - 2¹¹ = 81254753 is a prime.

It is not a weakly prime, because it can be changed into another prime (81256501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40628400 + 40628401.

It is an arithmetic number, because the mean of its divisors is an integer number (40628401).

Almost surely, 2^81256801 is an apocalyptic number.

It is an amenable number.

81256801 is a deficient number, since it is larger than the sum of its proper divisors (1).

81256801 is an equidigital number, since it uses as much as digits as its factorization.

81256801 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3840, while the sum is 31.

The square root of 81256801 is about 9014.2554323693. The cubic root of 81256801 is about 433.1316370351.

The spelling of 81256801 in words is "eighty-one million, two hundred fifty-six thousand, eight hundred one".