216701237981 has 2 divisors, whose sum is σ = 216701237982. Its totient is φ = 216701237980.

The previous prime is 216701237923. The next prime is 216701237983. The reversal of 216701237981 is 189732107612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 116104429081 + 100596808900 = 340741^2 + 317170^2 .

It is a cyclic number.

It is not a de Polignac number, because 216701237981 - 2³⁰ = 215627496157 is a prime.

It is a super-2 number, since 2×216701237981² (a number of 23 digits) contains 22 as substring.

Together with 216701237983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216701237983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108350618990 + 108350618991.

It is an arithmetic number, because the mean of its divisors is an integer number (108350618991).

Almost surely, 2^216701237981 is an apocalyptic number.

It is an amenable number.

216701237981 is a deficient number, since it is larger than the sum of its proper divisors (1).

216701237981 is an equidigital number, since it uses as much as digits as its factorization.

216701237981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 254016, while the sum is 47.

The spelling of 216701237981 in words is "two hundred sixteen billion, seven hundred one million, two hundred thirty-seven thousand, nine hundred eighty-one".