81577459 has 2 divisors, whose sum is σ = 81577460. Its totient is φ = 81577458.

The previous prime is 81577451. The next prime is 81577487. The reversal of 81577459 is 95477518.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81577459 - 2³ = 81577451 is a prime.

It is not a weakly prime, because it can be changed into another prime (81577451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40788729 + 40788730.

It is an arithmetic number, because the mean of its divisors is an integer number (40788730).

Almost surely, 2^81577459 is an apocalyptic number.

81577459 is a deficient number, since it is larger than the sum of its proper divisors (1).

81577459 is an equidigital number, since it uses as much as digits as its factorization.

81577459 is an evil number, because the sum of its binary digits is even.

The product of its digits is 352800, while the sum is 46.

The square root of 81577459 is about 9032.0240810131. The cubic root of 81577459 is about 433.7006348656.

The spelling of 81577459 in words is "eighty-one million, five hundred seventy-seven thousand, four hundred fifty-nine".