815894749 has 4 divisors (see below), whose sum is σ = 816751836. Its totient is φ = 815037664.

The previous prime is 815894743. The next prime is 815894759. The reversal of 815894749 is 947498518.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 494840025 + 321054724 = 22245^2 + 17918^2 .

It is a cyclic number.

It is not a de Polignac number, because 815894749 - 2²⁷ = 681677021 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 815894749.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (815894743) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 427114 + ... + 429019.

It is an arithmetic number, because the mean of its divisors is an integer number (204187959).

Almost surely, 2^815894749 is an apocalyptic number.

It is an amenable number.

815894749 is a deficient number, since it is larger than the sum of its proper divisors (857087).

815894749 is an equidigital number, since it uses as much as digits as its factorization.

815894749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 857086.

The product of its digits is 2903040, while the sum is 55.

The square root of 815894749 is about 28563.8713937729. The cubic root of 815894749 is about 934.4255668789.

The spelling of 815894749 in words is "eight hundred fifteen million, eight hundred ninety-four thousand, seven hundred forty-nine".