1221553316 has 6 divisors (see below), whose sum is σ = 2137718310. Its totient is φ = 610776656.

The previous prime is 1221553273. The next prime is 1221553321. The reversal of 1221553316 is 6133551221.

It can be written as a sum of positive squares in only one way, i.e., 1152330916 + 69222400 = 33946^2 + 8320^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 152694161 + ... + 152694168.

It is an arithmetic number, because the mean of its divisors is an integer number (356286385).

Almost surely, 2^1221553316 is an apocalyptic number.

It is an amenable number.

1221553316 is a deficient number, since it is larger than the sum of its proper divisors (916164994).

1221553316 is a wasteful number, since it uses less digits than its factorization.

1221553316 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 305388333 (or 305388331 counting only the distinct ones).

The product of its digits is 5400, while the sum is 29.

The square root of 1221553316 is about 34950.7269738413. The cubic root of 1221553316 is about 1068.9830253442.

The spelling of 1221553316 in words is "one billion, two hundred twenty-one million, five hundred fifty-three thousand, three hundred sixteen".