221515849 has 2 divisors, whose sum is σ = 221515850. Its totient is φ = 221515848.

The previous prime is 221515823. The next prime is 221515867. The reversal of 221515849 is 948515122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 202549824 + 18966025 = 14232^2 + 4355^2 .

It is a cyclic number.

It is not a de Polignac number, because 221515849 - 2¹¹ = 221513801 is a prime.

It is not a weakly prime, because it can be changed into another prime (221515649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110757924 + 110757925.

It is an arithmetic number, because the mean of its divisors is an integer number (110757925).

Almost surely, 2^221515849 is an apocalyptic number.

It is an amenable number.

221515849 is a deficient number, since it is larger than the sum of its proper divisors (1).

221515849 is an equidigital number, since it uses as much as digits as its factorization.

221515849 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28800, while the sum is 37.

The square root of 221515849 is about 14883.4085141812. The cubic root of 221515849 is about 605.0644004027.

The spelling of 221515849 in words is "two hundred twenty-one million, five hundred fifteen thousand, eight hundred forty-nine".