221409408 has 256 divisors, whose sum is σ = 697973760. Its totient is φ = 61501440.

The previous prime is 221409371. The next prime is 221409421. The reversal of 221409408 is 804904122.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4177510 + ... + 4177562.

It is an arithmetic number, because the mean of its divisors is an integer number (2726460).

Almost surely, 2^221409408 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221409408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (348986880).

221409408 is an abundant number, since it is smaller than the sum of its proper divisors (476564352).

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

221409408 is a wasteful number, since it uses less digits than its factorization.

221409408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147 (or 135 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 221409408 is about 14879.8322571190. The cubic root of 221409408 is about 604.9674713290.

The spelling of 221409408 in words is "two hundred twenty-one million, four hundred nine thousand, four hundred eight".