2215571221 has 2 divisors, whose sum is σ = 2215571222. Its totient is φ = 2215571220.

The previous prime is 2215571219. The next prime is 2215571263. The reversal of 2215571221 is 1221755122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2172864996 + 42706225 = 46614^2 + 6535^2 .

It is a cyclic number.

It is not a de Polignac number, because 2215571221 - 2¹ = 2215571219 is a prime.

Together with 2215571219, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 2215571221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2215571201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1107785610 + 1107785611.

It is an arithmetic number, because the mean of its divisors is an integer number (1107785611).

Almost surely, 2^2215571221 is an apocalyptic number.

It is an amenable number.

2215571221 is a deficient number, since it is larger than the sum of its proper divisors (1).

2215571221 is an equidigital number, since it uses as much as digits as its factorization.

2215571221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2800, while the sum is 28.

The square root of 2215571221 is about 47069.8546949106. The cubic root of 2215571221 is about 1303.6526899221.

It can be divided in two parts, 221557 and 1221, that added together give a triangular number (222778 = T₆₆₇).

The spelling of 2215571221 in words is "two billion, two hundred fifteen million, five hundred seventy-one thousand, two hundred twenty-one".