218147861 has 2 divisors, whose sum is σ = 218147862. Its totient is φ = 218147860.

The previous prime is 218147857. The next prime is 218147869. The reversal of 218147861 is 168741812.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 149572900 + 68574961 = 12230^2 + 8281^2 .

It is a cyclic number.

It is not a de Polignac number, because 218147861 - 2² = 218147857 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218147869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109073930 + 109073931.

It is an arithmetic number, because the mean of its divisors is an integer number (109073931).

Almost surely, 2^218147861 is an apocalyptic number.

It is an amenable number.

218147861 is a deficient number, since it is larger than the sum of its proper divisors (1).

218147861 is an equidigital number, since it uses as much as digits as its factorization.

218147861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21504, while the sum is 38.

The square root of 218147861 is about 14769.8294167536. The cubic root of 218147861 is about 601.9822044165.

The spelling of 218147861 in words is "two hundred eighteen million, one hundred forty-seven thousand, eight hundred sixty-one".