1221915849 has 16 divisors (see below), whose sum is σ = 2031237120. Its totient is φ = 634761360.

The previous prime is 1221915847. The next prime is 1221915869. The reversal of 1221915849 is 9485191221.

It is not a de Polignac number, because 1221915849 - 2¹ = 1221915847 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1221915849.

It is not an unprimeable number, because it can be changed into a prime (1221915847) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2644609 + ... + 2645070.

It is an arithmetic number, because the mean of its divisors is an integer number (126952320).

Almost surely, 2^1221915849 is an apocalyptic number.

It is an amenable number.

1221915849 is a deficient number, since it is larger than the sum of its proper divisors (809321271).

1221915849 is a wasteful number, since it uses less digits than its factorization.

1221915849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5289700.

The product of its digits is 51840, while the sum is 42.

The square root of 1221915849 is about 34955.9129332936. The cubic root of 1221915849 is about 1069.0887659304.

The spelling of 1221915849 in words is "one billion, two hundred twenty-one million, nine hundred fifteen thousand, eight hundred forty-nine".