81413451257 has 2 divisors, whose sum is σ = 81413451258. Its totient is φ = 81413451256.

The previous prime is 81413451199. The next prime is 81413451269. The reversal of 81413451257 is 75215431418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80919767296 + 493683961 = 284464^2 + 22219^2 .

It is a cyclic number.

It is not a de Polignac number, because 81413451257 - 2⁶ = 81413451193 is a prime.

It is not a weakly prime, because it can be changed into another prime (81413441257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40706725628 + 40706725629.

It is an arithmetic number, because the mean of its divisors is an integer number (40706725629).

Almost surely, 2^81413451257 is an apocalyptic number.

It is an amenable number.

81413451257 is a deficient number, since it is larger than the sum of its proper divisors (1).

81413451257 is an equidigital number, since it uses as much as digits as its factorization.

81413451257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 134400, while the sum is 41.

The spelling of 81413451257 in words is "eighty-one billion, four hundred thirteen million, four hundred fifty-one thousand, two hundred fifty-seven".