2221661989 has 2 divisors, whose sum is σ = 2221661990. Its totient is φ = 2221661988.

The previous prime is 2221661987. The next prime is 2221662019. The reversal of 2221661989 is 9891661222.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1566813889 + 654848100 = 39583^2 + 25590^2 .

It is a cyclic number.

It is not a de Polignac number, because 2221661989 - 2¹ = 2221661987 is a prime.

It is a super-2 number, since 2×2221661989² = 9871563986734872242, which contains 22 as substring.

Together with 2221661987, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2221661987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1110830994 + 1110830995.

It is an arithmetic number, because the mean of its divisors is an integer number (1110830995).

Almost surely, 2^2221661989 is an apocalyptic number.

It is an amenable number.

2221661989 is a deficient number, since it is larger than the sum of its proper divisors (1).

2221661989 is an equidigital number, since it uses as much as digits as its factorization.

2221661989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 186624, while the sum is 46.

The square root of 2221661989 is about 47134.5095338861. The cubic root of 2221661989 is about 1304.8462092272.

The spelling of 2221661989 in words is "two billion, two hundred twenty-one million, six hundred sixty-one thousand, nine hundred eighty-nine".