1216040021 has 8 divisors (see below), whose sum is σ = 1390650624. Its totient is φ = 1041652080.

The previous prime is 1216040011. The next prime is 1216040029. The reversal of 1216040021 is 1200406121.

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

It is not a de Polignac number, because 1216040021 - 2¹⁰ = 1216038997 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 (1216040029) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43790 + ... + 65951.

It is an arithmetic number, because the mean of its divisors is an integer number (173831328).

Almost surely, 2^1216040021 is an apocalyptic number.

It is an amenable number.

1216040021 is a deficient number, since it is larger than the sum of its proper divisors (174610603).

1216040021 is a wasteful number, since it uses less digits than its factorization.

1216040021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111331.

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

The square root of 1216040021 is about 34871.7653840467. The cubic root of 1216040021 is about 1067.3723690207.

Adding to 1216040021 its reverse (1200406121), we get a palindrome (2416446142).

The spelling of 1216040021 in words is "one billion, two hundred sixteen million, forty thousand, twenty-one".