1216655441 has 4 divisors (see below), whose sum is σ = 1218904884. Its totient is φ = 1214406000.

The previous prime is 1216655437. The next prime is 1216655491. The reversal of 1216655441 is 1445566121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1445566121 = 3833 ⋅377137.

It can be written as a sum of positive squares in 2 ways, for example, as 321449041 + 895206400 = 17929^2 + 29920^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216655441 - 2² = 1216655437 is a prime.

It is a super-2 number, since 2×1216655441² = 2960500924229808962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1216655411) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1123910 + ... + 1124991.

It is an arithmetic number, because the mean of its divisors is an integer number (304726221).

Almost surely, 2^1216655441 is an apocalyptic number.

It is an amenable number.

1216655441 is a deficient number, since it is larger than the sum of its proper divisors (2249443).

1216655441 is an equidigital number, since it uses as much as digits as its factorization.

1216655441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2249442.

The product of its digits is 28800, while the sum is 35.

The square root of 1216655441 is about 34880.5883121257. The cubic root of 1216655441 is about 1067.5523991486.

The spelling of 1216655441 in words is "one billion, two hundred sixteen million, six hundred fifty-five thousand, four hundred forty-one".