251151121 has 4 divisors (see below), whose sum is σ = 270470452. Its totient is φ = 231831792.

The previous prime is 251151113. The next prime is 251151137. The reversal of 251151121 is 121151152.

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 86285521 + 164865600 = 9289^2 + 12840^2 .

It is a cyclic number.

It is not a de Polignac number, because 251151121 - 2³ = 251151113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (251151521) 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, 9659646 + ... + 9659671.

It is an arithmetic number, because the mean of its divisors is an integer number (67617613).

Almost surely, 2^251151121 is an apocalyptic number.

It is an amenable number.

251151121 is a deficient number, since it is larger than the sum of its proper divisors (19319331).

251151121 is a wasteful number, since it uses less digits than its factorization.

251151121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19319330.

The product of its digits is 100, while the sum is 19.

The square root of 251151121 is about 15847.7481365650. The cubic root of 251151121 is about 630.9259257884.

The spelling of 251151121 in words is "two hundred fifty-one million, one hundred fifty-one thousand, one hundred twenty-one".