1555820 has 24 divisors (see below), whose sum is σ = 3734304. Its totient is φ = 533376.

The previous prime is 1555819. The next prime is 1555831. The reversal of 1555820 is 285551.

It is a self number, because there is not a number n which added to its sum of digits gives 1555820.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5417 + ... + 5696.

It is an arithmetic number, because the mean of its divisors is an integer number (155596).

2^1555820 is an apocalyptic number.

1555820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1555820 is an abundant number, since it is smaller than the sum of its proper divisors (2178484).

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

1555820 is a wasteful number, since it uses less digits than its factorization.

1555820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11129 (or 11127 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 26.

The square root of 1555820 is about 1247.3251380454. The cubic root of 1555820 is about 115.8741202856.

The spelling of 1555820 in words is "one million, five hundred fifty-five thousand, eight hundred twenty".