815901 has 4 divisors (see below), whose sum is σ = 1087872. Its totient is φ = 543932.

The previous prime is 815897. The next prime is 815923. The reversal of 815901 is 109518.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 815901 - 2² = 815897 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (815401) 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 in 3 ways as a sum of consecutive naturals, for example, 135981 + ... + 135986.

It is an arithmetic number, because the mean of its divisors is an integer number (271968).

2⁸¹⁵⁹⁰¹ is an apocalyptic number.

It is an amenable number.

815901 is a deficient number, since it is larger than the sum of its proper divisors (271971).

815901 is a wasteful number, since it uses less digits than its factorization.

815901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 271970.

The product of its (nonzero) digits is 360, while the sum is 24.

The square root of 815901 is about 903.2723841677. The cubic root of 815901 is about 93.4427953249.

The spelling of 815901 in words is "eight hundred fifteen thousand, nine hundred one".