1220555138 has 16 divisors (see below), whose sum is σ = 1998085536. Its totient is φ = 554571840.

The previous prime is 1220555113. The next prime is 1220555207. The reversal of 1220555138 is 8315550221.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51770 + ... + 71562.

It is an arithmetic number, because the mean of its divisors is an integer number (124880346).

Almost surely, 2^1220555138 is an apocalyptic number.

1220555138 is a deficient number, since it is larger than the sum of its proper divisors (777530398).

1220555138 is a wasteful number, since it uses less digits than its factorization.

1220555138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22609.

The product of its (nonzero) digits is 12000, while the sum is 32.

The square root of 1220555138 is about 34936.4442666966. Note that the first 3 decimals coincide. The cubic root of 1220555138 is about 1068.6917770090.

The spelling of 1220555138 in words is "one billion, two hundred twenty million, five hundred fifty-five thousand, one hundred thirty-eight".