221617628 has 12 divisors (see below), whose sum is σ = 397290432. Its totient is φ = 108106080.

The previous prime is 221617621. The next prime is 221617633. The reversal of 221617628 is 826716122.

It is a super-2 number, since 2×221617628² = 98228746080692768, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221617621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 675500 + ... + 675827.

It is an arithmetic number, because the mean of its divisors is an integer number (33107536).

Almost surely, 2^221617628 is an apocalyptic number.

It is an amenable number.

221617628 is a deficient number, since it is larger than the sum of its proper divisors (175672804).

221617628 is a wasteful number, since it uses less digits than its factorization.

221617628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1351372 (or 1351370 counting only the distinct ones).

The product of its digits is 16128, while the sum is 35.

The square root of 221617628 is about 14886.8273315707. The cubic root of 221617628 is about 605.1570550525.

The spelling of 221617628 in words is "two hundred twenty-one million, six hundred seventeen thousand, six hundred twenty-eight".