1221409915 has 32 divisors (see below), whose sum is σ = 1653903360. Its totient is φ = 858249600.

The previous prime is 1221409909. The next prime is 1221409961. The reversal of 1221409915 is 5199041221.

It is not a de Polignac number, because 1221409915 - 2¹¹ = 1221407867 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 201225 + ... + 207205.

It is an arithmetic number, because the mean of its divisors is an integer number (51684480).

Almost surely, 2^1221409915 is an apocalyptic number.

1221409915 is a deficient number, since it is larger than the sum of its proper divisors (432493445).

1221409915 is a wasteful number, since it uses less digits than its factorization.

1221409915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6123.

The product of its (nonzero) digits is 6480, while the sum is 34.

The square root of 1221409915 is about 34948.6754398504. The cubic root of 1221409915 is about 1068.9411935683.

The spelling of 1221409915 in words is "one billion, two hundred twenty-one million, four hundred nine thousand, nine hundred fifteen".