1251985349 has 4 divisors (see below), whose sum is σ = 1325631564. Its totient is φ = 1178339136.

The previous prime is 1251985309. The next prime is 1251985379. The reversal of 1251985349 is 9435891521.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 801909124 + 450076225 = 28318^2 + 21215^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1251985349 is a prime.

It is a super-2 number, since 2×1251985349² = 3134934628221303602, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251985309) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36823082 + ... + 36823115.

It is an arithmetic number, because the mean of its divisors is an integer number (331407891).

Almost surely, 2^1251985349 is an apocalyptic number.

It is an amenable number.

1251985349 is a deficient number, since it is larger than the sum of its proper divisors (73646215).

1251985349 is an equidigital number, since it uses as much as digits as its factorization.

1251985349 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73646214.

The product of its digits is 388800, while the sum is 47.

The square root of 1251985349 is about 35383.4049944321. The cubic root of 1251985349 is about 1077.7873506473.

The spelling of 1251985349 in words is "one billion, two hundred fifty-one million, nine hundred eighty-five thousand, three hundred forty-nine".