1216141721 has 16 divisors (see below), whose sum is σ = 1352755200. Its totient is φ = 1088060688.

The previous prime is 1216141711. The next prime is 1216141727. The reversal of 1216141721 is 1271416121.

It is a de Polignac number, because none of the positive numbers 2^k-1216141721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1216141727) 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, 16910 + ... + 52136.

It is an arithmetic number, because the mean of its divisors is an integer number (84547200).

Almost surely, 2^1216141721 is an apocalyptic number.

It is an amenable number.

1216141721 is a deficient number, since it is larger than the sum of its proper divisors (136613479).

1216141721 is a wasteful number, since it uses less digits than its factorization.

1216141721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35348.

The product of its digits is 672, while the sum is 26.

The square root of 1216141721 is about 34873.2235533224. The cubic root of 1216141721 is about 1067.4021237278.

Adding to 1216141721 its reverse (1271416121), we get a palindrome (2487557842).

The spelling of 1216141721 in words is "one billion, two hundred sixteen million, one hundred forty-one thousand, seven hundred twenty-one".