251996749 has 4 divisors (see below), whose sum is σ = 252041020. Its totient is φ = 251952480.

The previous prime is 251996743. The next prime is 251996777. The reversal of 251996749 is 947699152.

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 86359849 + 165636900 = 9293^2 + 12870^2 .

It is a cyclic number.

It is not a de Polignac number, because 251996749 - 2¹⁵ = 251963981 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 251996696 and 251996705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251996743) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 12072 + ... + 25489.

It is an arithmetic number, because the mean of its divisors is an integer number (63010255).

Almost surely, 2^251996749 is an apocalyptic number.

It is an amenable number.

251996749 is a deficient number, since it is larger than the sum of its proper divisors (44271).

251996749 is an equidigital number, since it uses as much as digits as its factorization.

251996749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44270.

The product of its digits is 1224720, while the sum is 52.

The square root of 251996749 is about 15874.4054691821. The cubic root of 251996749 is about 631.6332435522.

The spelling of 251996749 in words is "two hundred fifty-one million, nine hundred ninety-six thousand, seven hundred forty-nine".