1220555139 has 4 divisors (see below), whose sum is σ = 1627406856. Its totient is φ = 813703424.

The previous prime is 1220555113. The next prime is 1220555207. The reversal of 1220555139 is 9315550221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1220555139 - 2⁸ = 1220554883 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1220555339) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 203425854 + ... + 203425859.

It is an arithmetic number, because the mean of its divisors is an integer number (406851714).

Almost surely, 2^1220555139 is an apocalyptic number.

1220555139 is a deficient number, since it is larger than the sum of its proper divisors (406851717).

1220555139 is an equidigital number, since it uses as much as digits as its factorization.

1220555139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406851716.

The product of its (nonzero) digits is 13500, while the sum is 33.

The square root of 1220555139 is about 34936.4442810083. Note that the first 3 decimals coincide. The cubic root of 1220555139 is about 1068.6917773009.

The spelling of 1220555139 in words is "one billion, two hundred twenty million, five hundred fifty-five thousand, one hundred thirty-nine".