1221212143 has 2 divisors, whose sum is σ = 1221212144. Its totient is φ = 1221212142.

The previous prime is 1221212089. The next prime is 1221212147. The reversal of 1221212143 is 3412121221.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221212143 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1221212143.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221212147) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610606071 + 610606072.

It is an arithmetic number, because the mean of its divisors is an integer number (610606072).

Almost surely, 2^1221212143 is an apocalyptic number.

1221212143 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221212143 is an equidigital number, since it uses as much as digits as its factorization.

1221212143 is an evil number, because the sum of its binary digits is even.

The product of its digits is 192, while the sum is 19.

The square root of 1221212143 is about 34945.8458618474. The cubic root of 1221212143 is about 1068.8834957535.

Adding to 1221212143 its reverse (3412121221), we get a palindrome (4633333364).

The spelling of 1221212143 in words is "one billion, two hundred twenty-one million, two hundred twelve thousand, one hundred forty-three".