221606404 has 6 divisors (see below), whose sum is σ = 387811214. Its totient is φ = 110803200.

The previous prime is 221606393. The next prime is 221606417. The reversal of 221606404 is 404606122.

It can be written as a sum of positive squares in only one way, i.e., 219040000 + 2566404 = 14800^2 + 1602^2 .

It is a super-2 number, since 2×221606404² = 98218796587622432, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27700797 + ... + 27700804.

Almost surely, 2^221606404 is an apocalyptic number.

It is an amenable number.

221606404 is a deficient number, since it is larger than the sum of its proper divisors (166204810).

221606404 is a wasteful number, since it uses less digits than its factorization.

221606404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55401605 (or 55401603 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 221606404 is about 14886.4503492270. The cubic root of 221606404 is about 605.1468386609.

The spelling of 221606404 in words is "two hundred twenty-one million, six hundred six thousand, four hundred four".