1221550755 has 32 divisors (see below), whose sum is σ = 2063043840. Its totient is φ = 615496320.

The previous prime is 1221550741. The next prime is 1221550763. The reversal of 1221550755 is 5570551221.

1221550755 = T₁₁₃₃₀ + T₁₁₃₃₁ + ... + T₁₁₃₄₈.

It is not a de Polignac number, because 1221550755 - 2⁴ = 1221550739 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 100560 + ... + 112050.

It is an arithmetic number, because the mean of its divisors is an integer number (64470120).

Almost surely, 2^1221550755 is an apocalyptic number.

1221550755 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1221550755 is a deficient number, since it is larger than the sum of its proper divisors (841493085).

1221550755 is a wasteful number, since it uses less digits than its factorization.

1221550755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11891.

The product of its (nonzero) digits is 17500, while the sum is 33.

The square root of 1221550755 is about 34950.6903365298. The cubic root of 1221550755 is about 1068.9822782987.

The spelling of 1221550755 in words is "one billion, two hundred twenty-one million, five hundred fifty thousand, seven hundred fifty-five".