1220663161 has 6 divisors (see below), whose sum is σ = 1261310586. Its totient is φ = 1181286000.

The previous prime is 1220663159. The next prime is 1220663183. The reversal of 1220663161 is 1613660221.

1220663161 = T₂₀ + T₂₁ + ... + T₁₉₄₁.

It can be written as a sum of positive squares in only one way, i.e., 813390400 + 407272761 = 28520^2 + 20181^2 .

It is not a de Polignac number, because 1220663161 - 2¹ = 1220663159 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1220663141) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 634140 + ... + 636061.

It is an arithmetic number, because the mean of its divisors is an integer number (210218431).

Almost surely, 2^1220663161 is an apocalyptic number.

It is an amenable number.

1220663161 is a deficient number, since it is larger than the sum of its proper divisors (40647425).

1220663161 is an equidigital number, since it uses as much as digits as its factorization.

1220663161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1270263 (or 1270232 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 1220663161 is about 34937.9902255410. The cubic root of 1220663161 is about 1068.7233036160.

The spelling of 1220663161 in words is "one billion, two hundred twenty million, six hundred sixty-three thousand, one hundred sixty-one".