81932489 has 2 divisors, whose sum is σ = 81932490. Its totient is φ = 81932488.

The previous prime is 81932441. The next prime is 81932519. The reversal of 81932489 is 98423918.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72812089 + 9120400 = 8533^2 + 3020^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81932489 is a prime.

It is not a weakly prime, because it can be changed into another prime (81932419) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40966244 + 40966245.

It is an arithmetic number, because the mean of its divisors is an integer number (40966245).

Almost surely, 2^81932489 is an apocalyptic number.

It is an amenable number.

81932489 is a deficient number, since it is larger than the sum of its proper divisors (1).

81932489 is an equidigital number, since it uses as much as digits as its factorization.

81932489 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 124416, while the sum is 44.

The square root of 81932489 is about 9051.6566991905. The cubic root of 81932489 is about 434.3288880816.

The spelling of 81932489 in words is "eighty-one million, nine hundred thirty-two thousand, four hundred eighty-nine".