216601129 has 4 divisors (see below), whose sum is σ = 217340676. Its totient is φ = 215861584.

The previous prime is 216601111. The next prime is 216601139. The reversal of 216601129 is 921106612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 126787600 + 89813529 = 11260^2 + 9477^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216601129 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 216601097 and 216601106.

It is not an unprimeable number, because it can be changed into a prime (216601109) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 369334 + ... + 369919.

It is an arithmetic number, because the mean of its divisors is an integer number (54335169).

Almost surely, 2^216601129 is an apocalyptic number.

It is an amenable number.

216601129 is a deficient number, since it is larger than the sum of its proper divisors (739547).

216601129 is an equidigital number, since it uses as much as digits as its factorization.

216601129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 739546.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 216601129 is about 14717.3750716627. The cubic root of 216601129 is about 600.5560853818.

The spelling of 216601129 in words is "two hundred sixteen million, six hundred one thousand, one hundred twenty-nine".