1221109427 has 2 divisors, whose sum is σ = 1221109428. Its totient is φ = 1221109426.

The previous prime is 1221109411. The next prime is 1221109433. The reversal of 1221109427 is 7249011221.

It is a strong prime.

It is an emirp because it is prime and its reverse (7249011221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221109427 - 2⁴ = 1221109411 is a prime.

It is a super-2 number, since 2×1221109427² = 2982216465416536658, 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 1221109427.

It is not a weakly prime, because it can be changed into another prime (1221109457) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610554713 + 610554714.

It is an arithmetic number, because the mean of its divisors is an integer number (610554714).

Almost surely, 2^1221109427 is an apocalyptic number.

1221109427 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221109427 is an equidigital number, since it uses as much as digits as its factorization.

1221109427 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 1221109427 is about 34944.3761855896. The cubic root of 1221109427 is about 1068.8535270277.

The spelling of 1221109427 in words is "one billion, two hundred twenty-one million, one hundred nine thousand, four hundred twenty-seven".