1221556355 has 8 divisors (see below), whose sum is σ = 1490713200. Its totient is φ = 960681376.

The previous prime is 1221556319. The next prime is 1221556373. The reversal of 1221556355 is 5536551221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221556355 - 2⁸ = 1221556099 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2070140 + ... + 2070729.

It is an arithmetic number, because the mean of its divisors is an integer number (186339150).

Almost surely, 2^1221556355 is an apocalyptic number.

1221556355 is a deficient number, since it is larger than the sum of its proper divisors (269156845).

1221556355 is an equidigital number, since it uses as much as digits as its factorization.

1221556355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4140933.

The product of its digits is 45000, while the sum is 35.

The square root of 1221556355 is about 34950.7704493048. The cubic root of 1221556355 is about 1068.9839118211.

The spelling of 1221556355 in words is "one billion, two hundred twenty-one million, five hundred fifty-six thousand, three hundred fifty-five".