225921987 has 16 divisors (see below), whose sum is σ = 341016480. Its totient is φ = 147771936.

The previous prime is 225921973. The next prime is 225922003. The reversal of 225921987 is 789129522.

It is a happy number.

It is not a de Polignac number, because 225921987 - 2⁷ = 225921859 is a prime.

It is not an unprimeable number, because it can be changed into a prime (225921937) 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, 77508 + ... + 80369.

It is an arithmetic number, because the mean of its divisors is an integer number (21313530).

Almost surely, 2^225921987 is an apocalyptic number.

225921987 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

225921987 is a deficient number, since it is larger than the sum of its proper divisors (115094493).

225921987 is a wasteful number, since it uses less digits than its factorization.

225921987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157939 (or 157933 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The square root of 225921987 is about 15030.7014806362. The cubic root of 225921987 is about 609.0498394019.

The spelling of 225921987 in words is "two hundred twenty-five million, nine hundred twenty-one thousand, nine hundred eighty-seven".