221438138 has 16 divisors (see below), whose sum is σ = 336587400. Its totient is φ = 109252416.

The previous prime is 221438117. The next prime is 221438143. The reversal of 221438138 is 831834122.

221438138 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 87179569 + 134258569 = 9337^2 + 11587^2 .

It is a super-3 number, since 3×221438138³ (a number of 26 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44420 + ... + 49152.

Almost surely, 2^221438138 is an apocalyptic number.

221438138 is a deficient number, since it is larger than the sum of its proper divisors (115149262).

221438138 is a wasteful number, since it uses less digits than its factorization.

221438138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5041.

The product of its digits is 9216, while the sum is 32.

The square root of 221438138 is about 14880.7976264715. The cubic root of 221438138 is about 604.9936369797.

The spelling of 221438138 in words is "two hundred twenty-one million, four hundred thirty-eight thousand, one hundred thirty-eight".