815023681 has 4 divisors (see below), whose sum is σ = 818405764. Its totient is φ = 811641600.

The previous prime is 815023669. The next prime is 815023717. The reversal of 815023681 is 186320518.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 186320518 = 2 ⋅93160259.

It can be written as a sum of positive squares in 2 ways, for example, as 678133681 + 136890000 = 26041^2 + 11700^2 .

It is a cyclic number.

It is not a de Polignac number, because 815023681 - 2⁷ = 815023553 is a prime.

It is a super-2 number, since 2×815023681² = 1328527201181579522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (815023621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1690680 + ... + 1691161.

It is an arithmetic number, because the mean of its divisors is an integer number (204601441).

Almost surely, 2^815023681 is an apocalyptic number.

It is an amenable number.

815023681 is a deficient number, since it is larger than the sum of its proper divisors (3382083).

815023681 is a wasteful number, since it uses less digits than its factorization.

815023681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3382082.

The product of its (nonzero) digits is 11520, while the sum is 34.

The square root of 815023681 is about 28548.6195988528. The cubic root of 815023681 is about 934.0929103911.

The spelling of 815023681 in words is "eight hundred fifteen million, twenty-three thousand, six hundred eighty-one".