1221657105 has 16 divisors (see below), whose sum is σ = 1960197120. Its totient is φ = 649701888.

The previous prime is 1221657089. The next prime is 1221657119. The reversal of 1221657105 is 5017561221.

It is not a de Polignac number, because 1221657105 - 2⁴ = 1221657089 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 110065 + ... + 120654.

It is an arithmetic number, because the mean of its divisors is an integer number (122512320).

Almost surely, 2^1221657105 is an apocalyptic number.

1221657105 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221657105 is a deficient number, since it is larger than the sum of its proper divisors (738540015).

1221657105 is a wasteful number, since it uses less digits than its factorization.

1221657105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231080.

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

The square root of 1221657105 is about 34952.2117325928. The cubic root of 1221657105 is about 1069.0132997867.

The spelling of 1221657105 in words is "one billion, two hundred twenty-one million, six hundred fifty-seven thousand, one hundred five".