1256641775 has 24 divisors (see below), whose sum is σ = 1616094480. Its totient is φ = 968163840.

The previous prime is 1256641769. The next prime is 1256641787. The reversal of 1256641775 is 5771466521.

It is not a de Polignac number, because 1256641775 - 2¹⁶ = 1256576239 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 311924 + ... + 315926.

It is an arithmetic number, because the mean of its divisors is an integer number (67337270).

Almost surely, 2^1256641775 is an apocalyptic number.

1256641775 is a deficient number, since it is larger than the sum of its proper divisors (359452705).

1256641775 is a wasteful number, since it uses less digits than its factorization.

1256641775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4475 (or 4470 counting only the distinct ones).

The product of its digits is 352800, while the sum is 44.

The square root of 1256641775 is about 35449.1435016419. The cubic root of 1256641775 is about 1079.1218785213.

The spelling of 1256641775 in words is "one billion, two hundred fifty-six million, six hundred forty-one thousand, seven hundred seventy-five".