221381908 has 12 divisors (see below), whose sum is σ = 422638272. Its totient is φ = 100628120.

The previous prime is 221381903. The next prime is 221381947. The reversal of 221381908 is 809183122.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221381903) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2515660 + ... + 2515747.

It is an arithmetic number, because the mean of its divisors is an integer number (35219856).

Almost surely, 2^221381908 is an apocalyptic number.

It is an amenable number.

221381908 is a deficient number, since it is larger than the sum of its proper divisors (201256364).

221381908 is a wasteful number, since it uses less digits than its factorization.

221381908 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5031422 (or 5031420 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 221381908 is about 14878.9081588670. The cubic root of 221381908 is about 604.9424237720.

The spelling of 221381908 in words is "two hundred twenty-one million, three hundred eighty-one thousand, nine hundred eight".