1251253501 has 4 divisors (see below), whose sum is σ = 1251525600. Its totient is φ = 1250981404.

The previous prime is 1251253441. The next prime is 1251253511. The reversal of 1251253501 is 1053521521.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1053521521 = 13 ⋅81040117.

It is a cyclic number.

It is not a de Polignac number, because 1251253501 - 2²⁹ = 714382589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251253511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129031 + ... + 138388.

It is an arithmetic number, because the mean of its divisors is an integer number (312881400).

Almost surely, 2^1251253501 is an apocalyptic number.

It is an amenable number.

1251253501 is a deficient number, since it is larger than the sum of its proper divisors (272099).

1251253501 is an equidigital number, since it uses as much as digits as its factorization.

1251253501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 272098.

The product of its (nonzero) digits is 1500, while the sum is 25.

The square root of 1251253501 is about 35373.0617984929. The cubic root of 1251253501 is about 1077.5773028592.

The spelling of 1251253501 in words is "one billion, two hundred fifty-one million, two hundred fifty-three thousand, five hundred one".