251820049 has 4 divisors (see below), whose sum is σ = 271190836. Its totient is φ = 232449264.

The previous prime is 251820047. The next prime is 251820067. The reversal of 251820049 is 940028152.

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 88491649 + 163328400 = 9407^2 + 12780^2 .

It is a cyclic number.

It is not a de Polignac number, because 251820049 - 2¹ = 251820047 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 251820049.

It is not an unprimeable number, because it can be changed into a prime (251820043) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9685374 + ... + 9685399.

It is an arithmetic number, because the mean of its divisors is an integer number (67797709).

Almost surely, 2^251820049 is an apocalyptic number.

It is an amenable number.

251820049 is a deficient number, since it is larger than the sum of its proper divisors (19370787).

251820049 is a wasteful number, since it uses less digits than its factorization.

251820049 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19370786.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 251820049 is about 15868.8389304322. The cubic root of 251820049 is about 631.4855753890.

The spelling of 251820049 in words is "two hundred fifty-one million, eight hundred twenty thousand, forty-nine".