1220839 has 2 divisors, whose sum is σ = 1220840. Its totient is φ = 1220838.

The previous prime is 1220833. The next prime is 1220893. The reversal of 1220839 is 9380221.

Together with next prime (1220893) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is an emirp because it is prime and its reverse (9380221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1220839 - 2⁷ = 1220711 is a prime.

It is equal to p₉₄₄₀₈ and since 1220839 and 94408 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1220833) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610419 + 610420.

It is an arithmetic number, because the mean of its divisors is an integer number (610420).

2^1220839 is an apocalyptic number.

1220839 is a deficient number, since it is larger than the sum of its proper divisors (1).

1220839 is an equidigital number, since it uses as much as digits as its factorization.

1220839 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 1220839 is about 1104.9158338987. The cubic root of 1220839 is about 106.8774618404.

The spelling of 1220839 in words is "one million, two hundred twenty thousand, eight hundred thirty-nine".