221628438 has 48 divisors (see below), whose sum is σ = 490435296. Its totient is φ = 72316800.

The previous prime is 221628427. The next prime is 221628467. The reversal of 221628438 is 834826122.

221628438 is a `hidden beast` number, since 2 + 21 + 628 + 4 + 3 + 8 = 666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 197856 + ... + 198972.

It is an arithmetic number, because the mean of its divisors is an integer number (10217402).

Almost surely, 2^221628438 is an apocalyptic number.

221628438 is an abundant number, since it is smaller than the sum of its proper divisors (268806858).

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

221628438 is a wasteful number, since it uses less digits than its factorization.

221628438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1349 (or 1346 counting only the distinct ones).

The product of its digits is 36864, while the sum is 36.

The square root of 221628438 is about 14887.1903998034. The cubic root of 221628438 is about 605.1668942840.

The spelling of 221628438 in words is "two hundred twenty-one million, six hundred twenty-eight thousand, four hundred thirty-eight".