81435397 has 2 divisors, whose sum is σ = 81435398. Its totient is φ = 81435396.

The previous prime is 81435383. The next prime is 81435407. The reversal of 81435397 is 79353418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52983841 + 28451556 = 7279^2 + 5334^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81435397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81435337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40717698 + 40717699.

It is an arithmetic number, because the mean of its divisors is an integer number (40717699).

Almost surely, 2^81435397 is an apocalyptic number.

It is an amenable number.

81435397 is a deficient number, since it is larger than the sum of its proper divisors (1).

81435397 is an equidigital number, since it uses as much as digits as its factorization.

81435397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90720, while the sum is 40.

The square root of 81435397 is about 9024.1563040541. The cubic root of 81435397 is about 433.4487344850.

The spelling of 81435397 in words is "eighty-one million, four hundred thirty-five thousand, three hundred ninety-seven".