1555921 has 8 divisors (see below), whose sum is σ = 1638144. Its totient is φ = 1475760.

The previous prime is 1555919. The next prime is 1555943. The reversal of 1555921 is 1295551.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1555921 - 2¹ = 1555919 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 1555921.

It is not an unprimeable number, because it can be changed into a prime (1555901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1170 + ... + 2116.

It is an arithmetic number, because the mean of its divisors is an integer number (204768).

2^1555921 is an apocalyptic number.

It is an amenable number.

1555921 is a deficient number, since it is larger than the sum of its proper divisors (82223).

1555921 is an equidigital number, since it uses as much as digits as its factorization.

1555921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1031.

The product of its digits is 2250, while the sum is 28.

The square root of 1555921 is about 1247.3656240253. The cubic root of 1555921 is about 115.8766276521.

The spelling of 1555921 in words is "one million, five hundred fifty-five thousand, nine hundred twenty-one".