221628617 has 12 divisors (see below), whose sum is σ = 258264720. Its totient is φ = 189634536.

The previous prime is 221628613. The next prime is 221628619. The reversal of 221628617 is 716826122.

221628617 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 221628617 - 2² = 221628613 is a prime.

It is a super-3 number, since 3×221628617³ (a number of 26 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (221628613) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 26678 + ... + 33984.

It is an arithmetic number, because the mean of its divisors is an integer number (21522060).

Almost surely, 2^221628617 is an apocalyptic number.

It is an amenable number.

221628617 is a deficient number, since it is larger than the sum of its proper divisors (36636103).

221628617 is an equidigital number, since it uses as much as digits as its factorization.

221628617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7940 (or 7933 counting only the distinct ones).

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

The square root of 221628617 is about 14887.1964116821. The cubic root of 221628617 is about 605.1670572066.

The spelling of 221628617 in words is "two hundred twenty-one million, six hundred twenty-eight thousand, six hundred seventeen".