1256226561 has 6 divisors (see below), whose sum is σ = 1814549490. Its totient is φ = 837484368.

The previous prime is 1256226557. The next prime is 1256226583. The reversal of 1256226561 is 1656226521.

1256226561 is a `hidden beast` number, since 1 + 25 + 622 + 6 + 5 + 6 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 896403600 + 359822961 = 29940^2 + 18969^2 .

It is not a de Polignac number, because 1256226561 - 2² = 1256226557 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1256226541) 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, 69790356 + ... + 69790373.

It is an arithmetic number, because the mean of its divisors is an integer number (302424915).

Almost surely, 2^1256226561 is an apocalyptic number.

It is an amenable number.

1256226561 is a deficient number, since it is larger than the sum of its proper divisors (558322929).

1256226561 is a wasteful number, since it uses less digits than its factorization.

1256226561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139580735 (or 139580732 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 1256226561 is about 35443.2865434344. The cubic root of 1256226561 is about 1079.0030125408.

The spelling of 1256226561 in words is "one billion, two hundred fifty-six million, two hundred twenty-six thousand, five hundred sixty-one".