133221638 has 16 divisors (see below), whose sum is σ = 218211840. Its totient is φ = 60496200.

The previous prime is 133221637. The next prime is 133221691. The reversal of 133221638 is 836122331.

It is a self number, because there is not a number n which added to its sum of digits gives 133221638.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133221637) 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, 26723 + ... + 31313.

It is an arithmetic number, because the mean of its divisors is an integer number (13638240).

Almost surely, 2^133221638 is an apocalyptic number.

133221638 is a deficient number, since it is larger than the sum of its proper divisors (84990202).

133221638 is a wasteful number, since it uses less digits than its factorization.

133221638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5923.

The product of its digits is 5184, while the sum is 29.

The square root of 133221638 is about 11542.1678206479. The cubic root of 133221638 is about 510.7302597632.

Adding to 133221638 its reverse (836122331), we get a palindrome (969343969).

The spelling of 133221638 in words is "one hundred thirty-three million, two hundred twenty-one thousand, six hundred thirty-eight".