1251673642 has 4 divisors (see below), whose sum is σ = 1877510466. Its totient is φ = 625836820.

The previous prime is 1251673609. The next prime is 1251673667. The reversal of 1251673642 is 2463761521.

It is a Cunningham number, because it is equal to 35379²+1.

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

It can be written as a sum of positive squares in only one way, i.e., 1251673641 + 1 = 35379^2 + 1^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 312918409 + ... + 312918412.

Almost surely, 2^1251673642 is an apocalyptic number.

1251673642 is a deficient number, since it is larger than the sum of its proper divisors (625836824).

1251673642 is an equidigital number, since it uses as much as digits as its factorization.

1251673642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 625836823.

The product of its digits is 60480, while the sum is 37.

The square root of 1251673642 is about 35379.0000141327. Note that the first 4 decimals coincide. The cubic root of 1251673642 is about 1077.6978975914.

The spelling of 1251673642 in words is "one billion, two hundred fifty-one million, six hundred seventy-three thousand, six hundred forty-two".