1221165554959 has 8 divisors (see below), whose sum is σ = 1397046257568. Its totient is φ = 1045641972480.

The previous prime is 1221165554927. The next prime is 1221165554981. The reversal of 1221165554959 is 9594555611221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1221165554959 - 2⁵ = 1221165554927 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221165554459) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 89272702 + ... + 89286379.

It is an arithmetic number, because the mean of its divisors is an integer number (174630782196).

Almost surely, 2^{1221165554959} is an apocalyptic number.

1221165554959 is a deficient number, since it is larger than the sum of its proper divisors (175880702609).

1221165554959 is an equidigital number, since it uses as much as digits as its factorization.

1221165554959 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178560065.

The product of its digits is 4860000, while the sum is 55.

The spelling of 1221165554959 in words is "one trillion, two hundred twenty-one billion, one hundred sixty-five million, five hundred fifty-four thousand, nine hundred fifty-nine".