216211615981 has 8 divisors (see below), whose sum is σ = 221433604128. Its totient is φ = 211043742000.

The previous prime is 216211615913. The next prime is 216211615987. The reversal of 216211615981 is 189516112612.

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

It is a cyclic number.

It is not a de Polignac number, because 216211615981 - 2⁹ = 216211615469 is a prime.

It is a super-2 number, since 2×216211615981² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216211615987) 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, 13520455 + ... + 13536436.

It is an arithmetic number, because the mean of its divisors is an integer number (27679200516).

Almost surely, 2^216211615981 is an apocalyptic number.

It is an amenable number.

216211615981 is a deficient number, since it is larger than the sum of its proper divisors (5221988147).

216211615981 is a wasteful number, since it uses less digits than its factorization.

216211615981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27057083.

The product of its digits is 51840, while the sum is 43.

The spelling of 216211615981 in words is "two hundred sixteen billion, two hundred eleven million, six hundred fifteen thousand, nine hundred eighty-one".