1256641 has 9 divisors (see below), whose sum is σ = 1349121. Its totient is φ = 1170324.

The previous prime is 1256621. The next prime is 1256659. The reversal of 1256641 is 1466521.

The square root of 1256641 is 1121.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 1256641 - 2¹¹ = 1254593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1256611) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 21270 + ... + 21328.

2^1256641 is an apocalyptic number.

1256641 is the 1121-st square number.

1256641 is the 561-st centered octagonal number.

It is an amenable number.

1256641 is a deficient number, since it is larger than the sum of its proper divisors (92480).

1256641 is an frugal number, since it uses more digits than its factorization.

1256641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156 (or 78 counting only the distinct ones).

The product of its digits is 1440, while the sum is 25.

The cubic root of 1256641 is about 107.9121656681.

Multiplying 1256641 by its sum of digits (25), we get a square (31416025 = 5605²).

Multiplying 1256641 by its reverse (1466521), we get a square (1842890415961 = 1357531²).

The spelling of 1256641 in words is "one million, two hundred fifty-six thousand, six hundred forty-one".