221637138 has 8 divisors (see below), whose sum is σ = 443274288. Its totient is φ = 73879044.

The previous prime is 221637137. The next prime is 221637161. The reversal of 221637138 is 831736122.

221637138 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

221637138 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 221637099 and 221637108.

It is not an unprimeable number, because it can be changed into a prime (221637133) 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, 18469756 + ... + 18469767.

It is an arithmetic number, because the mean of its divisors is an integer number (55409286).

Almost surely, 2^221637138 is an apocalyptic number.

221637138 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

221637138 is a wasteful number, since it uses less digits than its factorization.

221637138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36939528.

The product of its digits is 12096, while the sum is 33.

The square root of 221637138 is about 14887.4825944483. The cubic root of 221637138 is about 605.1748127670.

The spelling of 221637138 in words is "two hundred twenty-one million, six hundred thirty-seven thousand, one hundred thirty-eight".