1815920 has 20 divisors (see below), whose sum is σ = 4222200. Its totient is φ = 726336.

The previous prime is 1815917. The next prime is 1815941. The reversal of 1815920 is 295181.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (20).

It is a self number, because there is not a number n which added to its sum of digits gives 1815920.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11270 + ... + 11429.

It is an arithmetic number, because the mean of its divisors is an integer number (211110).

2^1815920 is an apocalyptic number.

1815920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1815920 is an abundant number, since it is smaller than the sum of its proper divisors (2406280).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1815920 is a wasteful number, since it uses less digits than its factorization.

1815920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22712 (or 22706 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 1815920 is about 1347.5607592981. The cubic root of 1815920 is about 122.0016124485.

The spelling of 1815920 in words is "one million, eight hundred fifteen thousand, nine hundred twenty".