1561257 has 6 divisors (see below), whose sum is σ = 2255162. Its totient is φ = 1040832.

The previous prime is 1561247. The next prime is 1561267. The reversal of 1561257 is 7521651.

It is an interprime number because it is at equal distance from previous prime (1561247) and next prime (1561267).

It can be written as a sum of positive squares in only one way, i.e., 793881 + 767376 = 891^2 + 876^2 .

It is not a de Polignac number, because 1561257 - 2⁶ = 1561193 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 1561257.

It is not an unprimeable number, because it can be changed into a prime (1561247) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 86728 + ... + 86745.

2^1561257 is an apocalyptic number.

It is an amenable number.

1561257 is a deficient number, since it is larger than the sum of its proper divisors (693905).

1561257 is a wasteful number, since it uses less digits than its factorization.

1561257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173479 (or 173476 counting only the distinct ones).

The product of its digits is 2100, while the sum is 27.

The square root of 1561257 is about 1249.5027010775. The cubic root of 1561257 is about 116.0089420376.

The spelling of 1561257 in words is "one million, five hundred sixty-one thousand, two hundred fifty-seven".