1219991 has 2 divisors, whose sum is σ = 1219992. Its totient is φ = 1219990.

The previous prime is 1219963. The next prime is 1220027. The reversal of 1219991 is 1999121.

It is a weak prime.

It is an emirp because it is prime and its reverse (1999121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1219991 - 2¹⁴ = 1203607 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1219931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 609995 + 609996.

It is an arithmetic number, because the mean of its divisors is an integer number (609996).

2^1219991 is an apocalyptic number.

1219991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1219991 is an equidigital number, since it uses as much as digits as its factorization.

1219991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1458, while the sum is 32.

The square root of 1219991 is about 1104.5320276026. The cubic root of 1219991 is about 106.8527102610.

The spelling of 1219991 in words is "one million, two hundred nineteen thousand, nine hundred ninety-one".