816145581 has 8 divisors (see below), whose sum is σ = 1088458560. Its totient is φ = 543964832.

The previous prime is 816145573. The next prime is 816145597. The reversal of 816145581 is 185541618.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 816145581 - 2³ = 816145573 is a prime.

It is a super-2 number, since 2×816145581² = 1332187218771655122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816145511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17625 + ... + 44078.

It is an arithmetic number, because the mean of its divisors is an integer number (136057320).

Almost surely, 2^816145581 is an apocalyptic number.

It is an amenable number.

816145581 is a deficient number, since it is larger than the sum of its proper divisors (272312979).

816145581 is a wasteful number, since it uses less digits than its factorization.

816145581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66115.

The product of its digits is 38400, while the sum is 39.

The square root of 816145581 is about 28568.2617777141. The cubic root of 816145581 is about 934.5213144489.

The spelling of 816145581 in words is "eight hundred sixteen million, one hundred forty-five thousand, five hundred eighty-one".