1221990239 has 2 divisors, whose sum is σ = 1221990240. Its totient is φ = 1221990238.

The previous prime is 1221990233. The next prime is 1221990293. The reversal of 1221990239 is 9320991221.

Together with next prime (1221990293) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1221990239 - 2⁸ = 1221989983 is a prime.

It is a super-2 number, since 2×1221990239² = 2986520288422554242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221990233) 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, 610995119 + 610995120.

It is an arithmetic number, because the mean of its divisors is an integer number (610995120).

Almost surely, 2^1221990239 is an apocalyptic number.

1221990239 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221990239 is an equidigital number, since it uses as much as digits as its factorization.

1221990239 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17496, while the sum is 38.

The square root of 1221990239 is about 34956.9769717005. The cubic root of 1221990239 is about 1069.1104607957.

The spelling of 1221990239 in words is "one billion, two hundred twenty-one million, nine hundred ninety thousand, two hundred thirty-nine".