1555901 has 2 divisors, whose sum is σ = 1555902. Its totient is φ = 1555900.

The previous prime is 1555861. The next prime is 1555907. The reversal of 1555901 is 1095551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1207801 + 348100 = 1099^2 + 590^2 .

It is an emirp because it is prime and its reverse (1095551) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1555901 - 2⁶ = 1555837 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is equal to p₁₁₈₀₇₉ and since 1555901 and 118079 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1555907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 777950 + 777951.

It is an arithmetic number, because the mean of its divisors is an integer number (777951).

2^1555901 is an apocalyptic number.

It is an amenable number.

1555901 is a deficient number, since it is larger than the sum of its proper divisors (1).

1555901 is an equidigital number, since it uses as much as digits as its factorization.

1555901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1125, while the sum is 26.

The square root of 1555901 is about 1247.3576071039. The cubic root of 1555901 is about 115.8761311525.

The spelling of 1555901 in words is "one million, five hundred fifty-five thousand, nine hundred one".