251991779836 has 12 divisors (see below), whose sum is σ = 441325628128. Its totient is φ = 125898743232.

The previous prime is 251991779833. The next prime is 251991779839. The reversal of 251991779836 is 638977199152.

It is an interprime number because it is at equal distance from previous prime (251991779833) and next prime (251991779839).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251991779833) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24280836 + ... + 24291211.

Almost surely, 2^251991779836 is an apocalyptic number.

It is an amenable number.

251991779836 is a deficient number, since it is larger than the sum of its proper divisors (189333848292).

251991779836 is a wasteful number, since it uses less digits than its factorization.

251991779836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48573348 (or 48573346 counting only the distinct ones).

The product of its digits is 51438240, while the sum is 67.

The spelling of 251991779836 in words is "two hundred fifty-one billion, nine hundred ninety-one million, seven hundred seventy-nine thousand, eight hundred thirty-six".