1251928409 has 4 divisors (see below), whose sum is σ = 1258483200. Its totient is φ = 1245373620.

The previous prime is 1251928361. The next prime is 1251928429. The reversal of 1251928409 is 9048291521.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1251928409 is a prime.

It is a super-2 number, since 2×1251928409² = 3134649482522542562, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1251928429) 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, 3277109 + ... + 3277490.

It is an arithmetic number, because the mean of its divisors is an integer number (314620800).

Almost surely, 2^1251928409 is an apocalyptic number.

It is an amenable number.

1251928409 is a deficient number, since it is larger than the sum of its proper divisors (6554791).

1251928409 is an equidigital number, since it uses as much as digits as its factorization.

1251928409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6554790.

The product of its (nonzero) digits is 51840, while the sum is 41.

The square root of 1251928409 is about 35382.6003708037. The cubic root of 1251928409 is about 1077.7710112277.

The spelling of 1251928409 in words is "one billion, two hundred fifty-one million, nine hundred twenty-eight thousand, four hundred nine".