221261616 has 30 divisors (see below), whose sum is σ = 619225620. Its totient is φ = 73753824.

The previous prime is 221261611. The next prime is 221261629. The reversal of 221261616 is 616162122.

221261616 is a `hidden beast` number, since 2 + 21 + 26 + 1 + 616 = 666.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 221261616.

It is not an unprimeable number, because it can be changed into a prime (221261611) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 768126 + ... + 768413.

It is an arithmetic number, because the mean of its divisors is an integer number (20640854).

Almost surely, 2^221261616 is an apocalyptic number.

It is an amenable number.

221261616 is an abundant number, since it is smaller than the sum of its proper divisors (397964004).

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

221261616 is a wasteful number, since it uses less digits than its factorization.

221261616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1536553 (or 1536544 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 221261616 is about 14874.8652430871. The cubic root of 221261616 is about 604.8328349940.

The spelling of 221261616 in words is "two hundred twenty-one million, two hundred sixty-one thousand, six hundred sixteen".