1216004021 has 8 divisors (see below), whose sum is σ = 1220940864. Its totient is φ = 1211078080.

The previous prime is 1216004003. The next prime is 1216004087. The reversal of 1216004021 is 1204006121.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1216004021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216064021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 274736 + ... + 279126.

It is an arithmetic number, because the mean of its divisors is an integer number (152617608).

Almost surely, 2^1216004021 is an apocalyptic number.

It is an amenable number.

1216004021 is a deficient number, since it is larger than the sum of its proper divisors (4936843).

1216004021 is an equidigital number, since it uses as much as digits as its factorization.

1216004021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5451.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 1216004021 is about 34871.2492033193. The cubic root of 1216004021 is about 1067.3618359834.

The spelling of 1216004021 in words is "one billion, two hundred sixteen million, four thousand, twenty-one".