251220225 has 12 divisors (see below), whose sum is σ = 415350896. Its totient is φ = 133984080.

The previous prime is 251220209. The next prime is 251220227. The reversal of 251220225 is 522022152.

It is not a de Polignac number, because 251220225 - 2⁴ = 251220209 is a prime.

It is a super-2 number, since 2×251220225² = 126223202898101250, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (251220227) 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 11 ways as a sum of consecutive naturals, for example, 1674727 + ... + 1674876.

Almost surely, 2^251220225 is an apocalyptic number.

251220225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

251220225 is a deficient number, since it is larger than the sum of its proper divisors (164130671).

251220225 is a wasteful number, since it uses less digits than its factorization.

251220225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3349616 (or 3349611 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 21.

The square root of 251220225 is about 15849.9282332760. The cubic root of 251220225 is about 630.9837867114.

Adding to 251220225 its reverse (522022152), we get a palindrome (773242377).

The spelling of 251220225 in words is "two hundred fifty-one million, two hundred twenty thousand, two hundred twenty-five".