1216602401 has 4 divisors (see below), whose sum is σ = 1390402752. Its totient is φ = 1042802052.

The previous prime is 1216602391. The next prime is 1216602427. The reversal of 1216602401 is 1042066121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1042066121 = 1451 ⋅718171.

It is a cyclic number.

It is not a de Polignac number, because 1216602401 - 2⁶ = 1216602337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1216602481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86900165 + ... + 86900178.

It is an arithmetic number, because the mean of its divisors is an integer number (347600688).

Almost surely, 2^1216602401 is an apocalyptic number.

It is an amenable number.

1216602401 is a deficient number, since it is larger than the sum of its proper divisors (173800351).

1216602401 is an equidigital number, since it uses as much as digits as its factorization.

1216602401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173800350.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 1216602401 is about 34879.8279955621. The cubic root of 1216602401 is about 1067.5368856350.

Adding to 1216602401 its reverse (1042066121), we get a palindrome (2258668522).

The spelling of 1216602401 in words is "one billion, two hundred sixteen million, six hundred two thousand, four hundred one".