1221655107 has 4 divisors (see below), whose sum is σ = 1628873480. Its totient is φ = 814436736.

The previous prime is 1221655093. The next prime is 1221655111. The reversal of 1221655107 is 7015561221.

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

It is not a de Polignac number, because 1221655107 - 2¹⁴ = 1221638723 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221655157) 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, 203609182 + ... + 203609187.

It is an arithmetic number, because the mean of its divisors is an integer number (407218370).

Almost surely, 2^1221655107 is an apocalyptic number.

1221655107 is a deficient number, since it is larger than the sum of its proper divisors (407218373).

1221655107 is an equidigital number, since it uses as much as digits as its factorization.

1221655107 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407218372.

The product of its (nonzero) digits is 4200, while the sum is 30.

The square root of 1221655107 is about 34952.1831506989. The cubic root of 1221655107 is about 1069.0127170019.

The spelling of 1221655107 in words is "one billion, two hundred twenty-one million, six hundred fifty-five thousand, one hundred seven".