1221124391 has 2 divisors, whose sum is σ = 1221124392. Its totient is φ = 1221124390.

The previous prime is 1221124381. The next prime is 1221124417. The reversal of 1221124391 is 1934211221.

It is an a-pointer prime, because the next prime (1221124417) can be obtained adding 1221124391 to its sum of digits (26).

It is a weak prime.

It is an emirp because it is prime and its reverse (1934211221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221124391 - 2⁶ = 1221124327 is a prime.

It is a super-2 number, since 2×1221124391² = 2982289556590241762, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1221124391.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221124321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610562195 + 610562196.

It is an arithmetic number, because the mean of its divisors is an integer number (610562196).

Almost surely, 2^1221124391 is an apocalyptic number.

1221124391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221124391 is an equidigital number, since it uses as much as digits as its factorization.

1221124391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 864, while the sum is 26.

The square root of 1221124391 is about 34944.5902966396. The cubic root of 1221124391 is about 1068.8578930734.

The spelling of 1221124391 in words is "one billion, two hundred twenty-one million, one hundred twenty-four thousand, three hundred ninety-one".