1221555042425 has 24 divisors (see below), whose sum is σ = 1555662228120. Its totient is φ = 950957580800.

The previous prime is 1221555042413. The next prime is 1221555042431. The reversal of 1221555042425 is 5242405551221.

It can be written as a sum of positive squares in 12 ways, for example, as 1153097982976 + 68457059449 = 1073824^2 + 261643^2 .

It is not a de Polignac number, because 1221555042425 - 2¹⁰ = 1221555041401 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1133102 + ... + 1930551.

It is an arithmetic number, because the mean of its divisors is an integer number (64819259505).

Almost surely, 2^{1221555042425} is an apocalyptic number.

It is an amenable number.

1221555042425 is a deficient number, since it is larger than the sum of its proper divisors (334107185695).

1221555042425 is a wasteful number, since it uses less digits than its factorization.

1221555042425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3064093 (or 3064088 counting only the distinct ones).

The product of its (nonzero) digits is 160000, while the sum is 38.

The spelling of 1221555042425 in words is "one trillion, two hundred twenty-one billion, five hundred fifty-five million, forty-two thousand, four hundred twenty-five".