221256678 has 16 divisors (see below), whose sum is σ = 442828800. Its totient is φ = 73699656.

The previous prime is 221256677. The next prime is 221256731. The reversal of 221256678 is 876652122.

221256678 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221256677) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3478 + ... + 21321.

It is an arithmetic number, because the mean of its divisors is an integer number (27676800).

Almost surely, 2^221256678 is an apocalyptic number.

221256678 is an abundant number, since it is smaller than the sum of its proper divisors (221572122).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221256678 is a wasteful number, since it uses less digits than its factorization.

221256678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26291.

The product of its digits is 80640, while the sum is 39.

The square root of 221256678 is about 14874.6992574640. The cubic root of 221256678 is about 604.8283355139.

The spelling of 221256678 in words is "two hundred twenty-one million, two hundred fifty-six thousand, six hundred seventy-eight".