221661055 has 48 divisors (see below), whose sum is σ = 339958944. Its totient is φ = 137195520.

The previous prime is 221661031. The next prime is 221661073. The reversal of 221661055 is 550166122.

It is not a de Polignac number, because 221661055 - 2⁵ = 221661023 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 627759 + ... + 628111.

It is an arithmetic number, because the mean of its divisors is an integer number (7082478).

Almost surely, 2^221661055 is an apocalyptic number.

221661055 is a deficient number, since it is larger than the sum of its proper divisors (118297889).

221661055 is a wasteful number, since it uses less digits than its factorization.

221661055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 616 (or 609 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 221661055 is about 14888.2858314851. The cubic root of 221661055 is about 605.1965802463.

The spelling of 221661055 in words is "two hundred twenty-one million, six hundred sixty-one thousand, fifty-five".