225351021 has 16 divisors (see below), whose sum is σ = 343724544. Its totient is φ = 128647344.

The previous prime is 225351017. The next prime is 225351023. The reversal of 225351021 is 120153522.

It is not a de Polignac number, because 225351021 - 2² = 225351017 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (225351023) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 19810 + ... + 29036.

It is an arithmetic number, because the mean of its divisors is an integer number (21482784).

Almost surely, 2^225351021 is an apocalyptic number.

225351021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

225351021 is a deficient number, since it is larger than the sum of its proper divisors (118373523).

225351021 is a wasteful number, since it uses less digits than its factorization.

225351021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10400.

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 225351021 is about 15011.6961400103. The cubic root of 225351021 is about 608.5363286435.

The spelling of 225351021 in words is "two hundred twenty-five million, three hundred fifty-one thousand, twenty-one".