1251457643 has 2 divisors, whose sum is σ = 1251457644. Its totient is φ = 1251457642.

The previous prime is 1251457609. The next prime is 1251457657. The reversal of 1251457643 is 3467541521.

It is a strong prime.

It is an emirp because it is prime and its reverse (3467541521) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1251457643 - 2¹² = 1251453547 is a prime.

It is a super-2 number, since 2×1251457643² = 3132292464446230898, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1251457597 and 1251457606.

It is not a weakly prime, because it can be changed into another prime (1251457843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 625728821 + 625728822.

It is an arithmetic number, because the mean of its divisors is an integer number (625728822).

Almost surely, 2^1251457643 is an apocalyptic number.

1251457643 is a deficient number, since it is larger than the sum of its proper divisors (1).

1251457643 is an equidigital number, since it uses as much as digits as its factorization.

1251457643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 100800, while the sum is 38.

The square root of 1251457643 is about 35375.9472382013. The cubic root of 1251457643 is about 1077.6359019157.

The spelling of 1251457643 in words is "one billion, two hundred fifty-one million, four hundred fifty-seven thousand, six hundred forty-three".