251421145 has 4 divisors (see below), whose sum is σ = 301705380. Its totient is φ = 201136912.

The previous prime is 251421133. The next prime is 251421151. The reversal of 251421145 is 541124152.

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 197486809 + 53934336 = 14053^2 + 7344^2 .

It is a cyclic number.

It is not a de Polignac number, because 251421145 - 2¹¹ = 251419097 is a prime.

It is a super-2 number, since 2×251421145² = 126425184306222050, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25142110 + ... + 25142119.

It is an arithmetic number, because the mean of its divisors is an integer number (75426345).

Almost surely, 2^251421145 is an apocalyptic number.

It is an amenable number.

251421145 is a deficient number, since it is larger than the sum of its proper divisors (50284235).

251421145 is an equidigital number, since it uses as much as digits as its factorization.

251421145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50284234.

The product of its digits is 1600, while the sum is 25.

The square root of 251421145 is about 15856.2651655426. The cubic root of 251421145 is about 631.1519571942.

Adding to 251421145 its reverse (541124152), we get a palindrome (792545297).

The spelling of 251421145 in words is "two hundred fifty-one million, four hundred twenty-one thousand, one hundred forty-five".