1251040261 has 2 divisors, whose sum is σ = 1251040262. Its totient is φ = 1251040260.

The previous prime is 1251040223. The next prime is 1251040283. The reversal of 1251040261 is 1620401521.

It is an a-pointer prime, because the next prime (1251040283) can be obtained adding 1251040261 to its sum of digits (22).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1178892225 + 72148036 = 34335^2 + 8494^2 .

It is a cyclic number.

It is not a de Polignac number, because 1251040261 - 2¹⁵ = 1251007493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1251040211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 625520130 + 625520131.

It is an arithmetic number, because the mean of its divisors is an integer number (625520131).

Almost surely, 2^1251040261 is an apocalyptic number.

It is an amenable number.

1251040261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1251040261 is an equidigital number, since it uses as much as digits as its factorization.

1251040261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 1251040261 is about 35370.0475119839. The cubic root of 1251040261 is about 1077.5160854111.

Adding to 1251040261 its reverse (1620401521), we get a palindrome (2871441782).

The spelling of 1251040261 in words is "one billion, two hundred fifty-one million, forty thousand, two hundred sixty-one".