1221204615 has 16 divisors (see below), whose sum is σ = 1981449216. Its totient is φ = 642135200.

The previous prime is 1221204583. The next prime is 1221204643. The reversal of 1221204615 is 5164021221.

It is not a de Polignac number, because 1221204615 - 2⁵ = 1221204583 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 572271 + ... + 574400.

It is an arithmetic number, because the mean of its divisors is an integer number (123840576).

Almost surely, 2^1221204615 is an apocalyptic number.

1221204615 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1221204615 is a deficient number, since it is larger than the sum of its proper divisors (760244601).

1221204615 is a wasteful number, since it uses less digits than its factorization.

1221204615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1146750.

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 1221204615 is about 34945.7381521696. The cubic root of 1221204615 is about 1068.8812994189.

Adding to 1221204615 its reverse (5164021221), we get a palindrome (6385225836).

The spelling of 1221204615 in words is "one billion, two hundred twenty-one million, two hundred four thousand, six hundred fifteen".