81040579 has 2 divisors, whose sum is σ = 81040580. Its totient is φ = 81040578.

The previous prime is 81040543. The next prime is 81040613. The reversal of 81040579 is 97504018.

It is a happy number.

It is an a-pointer prime, because the next prime (81040613) can be obtained adding 81040579 to its sum of digits (34).

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81040579 is a prime.

It is not a weakly prime, because it can be changed into another prime (81040979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40520289 + 40520290.

It is an arithmetic number, because the mean of its divisors is an integer number (40520290).

Almost surely, 2^81040579 is an apocalyptic number.

81040579 is a deficient number, since it is larger than the sum of its proper divisors (1).

81040579 is an equidigital number, since it uses as much as digits as its factorization.

81040579 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 81040579 is about 9002.2541066113. The cubic root of 81040579 is about 432.7471121723.

The spelling of 81040579 in words is "eighty-one million, forty thousand, five hundred seventy-nine".