1245996781 has 2 divisors, whose sum is σ = 1245996782. Its totient is φ = 1245996780.

The previous prime is 1245996761. The next prime is 1245996809. The reversal of 1245996781 is 1876995421.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 911436100 + 334560681 = 30190^2 + 18291^2 .

It is a cyclic number.

It is not a de Polignac number, because 1245996781 - 2²⁵ = 1212442349 is a prime.

It is a super-2 number, since 2×1245996781² = 3105015956524723922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1245996761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 622998390 + 622998391.

It is an arithmetic number, because the mean of its divisors is an integer number (622998391).

Almost surely, 2^1245996781 is an apocalyptic number.

It is an amenable number.

1245996781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1245996781 is an equidigital number, since it uses as much as digits as its factorization.

1245996781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1088640, while the sum is 52.

The square root of 1245996781 is about 35298.6795928686. The cubic root of 1245996781 is about 1076.0661587016.

The spelling of 1245996781 in words is "one billion, two hundred forty-five million, nine hundred ninety-six thousand, seven hundred eighty-one".