1249551761 has 2 divisors, whose sum is σ = 1249551762. Its totient is φ = 1249551760.

The previous prime is 1249551713. The next prime is 1249551773. The reversal of 1249551761 is 1671559421.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 636048400 + 613503361 = 25220^2 + 24769^2 .

It is a cyclic number.

It is not a de Polignac number, because 1249551761 - 2¹⁸ = 1249289617 is a prime.

It is a super-2 number, since 2×1249551761² = 3122759206836402242, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1249557761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 624775880 + 624775881.

It is an arithmetic number, because the mean of its divisors is an integer number (624775881).

Almost surely, 2^1249551761 is an apocalyptic number.

It is an amenable number.

1249551761 is a deficient number, since it is larger than the sum of its proper divisors (1).

1249551761 is an equidigital number, since it uses as much as digits as its factorization.

1249551761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 75600, while the sum is 41.

The square root of 1249551761 is about 35348.9994342131. Note that the first 3 decimals coincide. The cubic root of 1249551761 is about 1077.0885694020.

The spelling of 1249551761 in words is "one billion, two hundred forty-nine million, five hundred fifty-one thousand, seven hundred sixty-one".