1216021717 has 16 divisors (see below), whose sum is σ = 1323174400. Its totient is φ = 1113289920.

The previous prime is 1216021699. The next prime is 1216021739. The reversal of 1216021717 is 7171206121.

It is a cyclic number.

It is not a de Polignac number, because 1216021717 - 2¹⁹ = 1215497429 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 (1216021117) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 727759 + ... + 729427.

It is an arithmetic number, because the mean of its divisors is an integer number (82698400).

Almost surely, 2^1216021717 is an apocalyptic number.

It is an amenable number.

1216021717 is a deficient number, since it is larger than the sum of its proper divisors (107152683).

1216021717 is a wasteful number, since it uses less digits than its factorization.

1216021717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2956.

The product of its (nonzero) digits is 1176, while the sum is 28.

The square root of 1216021717 is about 34871.5029357784. The cubic root of 1216021717 is about 1067.3670135824.

Adding to 1216021717 its reverse (7171206121), we get a palindrome (8387227838).

The spelling of 1216021717 in words is "one billion, two hundred sixteen million, twenty-one thousand, seven hundred seventeen".