1263720251 has 2 divisors, whose sum is σ = 1263720252. Its totient is φ = 1263720250.

The previous prime is 1263720223. The next prime is 1263720281. The reversal of 1263720251 is 1520273621.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (1520273621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1263720251 - 2⁶ = 1263720187 is a prime.

It is not a weakly prime, because it can be changed into another prime (1263720281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 631860125 + 631860126.

It is an arithmetic number, because the mean of its divisors is an integer number (631860126).

Almost surely, 2^1263720251 is an apocalyptic number.

1263720251 is a deficient number, since it is larger than the sum of its proper divisors (1).

1263720251 is an equidigital number, since it uses as much as digits as its factorization.

1263720251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 1263720251 is about 35548.8431738643. The cubic root of 1263720251 is about 1081.1442636153.

Adding to 1263720251 its reverse (1520273621), we get a palindrome (2783993872).

The spelling of 1263720251 in words is "one billion, two hundred sixty-three million, seven hundred twenty thousand, two hundred fifty-one".