221678725 has 24 divisors (see below), whose sum is σ = 292481280. Its totient is φ = 166091520.

The previous prime is 221678713. The next prime is 221678731. The reversal of 221678725 is 527876122.

It is a happy number.

It is not a de Polignac number, because 221678725 - 2⁵ = 221678693 is a prime.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 93606 + ... + 95944.

It is an arithmetic number, because the mean of its divisors is an integer number (12186720).

Almost surely, 2^221678725 is an apocalyptic number.

221678725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

221678725 is a deficient number, since it is larger than the sum of its proper divisors (70802555).

221678725 is a wasteful number, since it uses less digits than its factorization.

221678725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2589 (or 2584 counting only the distinct ones).

The product of its digits is 94080, while the sum is 40.

The square root of 221678725 is about 14888.8792392174. The cubic root of 221678725 is about 605.2126611638.

The spelling of 221678725 in words is "two hundred twenty-one million, six hundred seventy-eight thousand, seven hundred twenty-five".