81645059 has 2 divisors, whose sum is σ = 81645060. Its totient is φ = 81645058.

The previous prime is 81645049. The next prime is 81645073. The reversal of 81645059 is 95054618.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81645059 is a prime.

It is a super-2 number, since 2×81645059² = 13331831318226962, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81645019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40822529 + 40822530.

It is an arithmetic number, because the mean of its divisors is an integer number (40822530).

Almost surely, 2^81645059 is an apocalyptic number.

81645059 is a deficient number, since it is larger than the sum of its proper divisors (1).

81645059 is an equidigital number, since it uses as much as digits as its factorization.

81645059 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 43200, while the sum is 38.

The square root of 81645059 is about 9035.7655458738. The cubic root of 81645059 is about 433.8203986204.

The spelling of 81645059 in words is "eighty-one million, six hundred forty-five thousand, fifty-nine".