216661051601 has 16 divisors (see below), whose sum is σ = 222306315264. Its totient is φ = 211043995344.

The previous prime is 216661051591. The next prime is 216661051609. The reversal of 216661051601 is 106150166612.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216661051601 is a prime.

It is a super-2 number, since 2×216661051601² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216661051609) 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, 43617620 + ... + 43622586.

It is an arithmetic number, because the mean of its divisors is an integer number (13894144704).

Almost surely, 2^216661051601 is an apocalyptic number.

It is an amenable number.

216661051601 is a deficient number, since it is larger than the sum of its proper divisors (5645263663).

216661051601 is a wasteful number, since it uses less digits than its factorization.

216661051601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7580.

The product of its (nonzero) digits is 12960, while the sum is 35.

The spelling of 216661051601 in words is "two hundred sixteen billion, six hundred sixty-one million, fifty-one thousand, six hundred one".