618661213 has 2 divisors, whose sum is σ = 618661214. Its totient is φ = 618661212.

The previous prime is 618661193. The next prime is 618661217. The reversal of 618661213 is 312166816.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 611968644 + 6692569 = 24738^2 + 2587^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-618661213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (618661217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 309330606 + 309330607.

It is an arithmetic number, because the mean of its divisors is an integer number (309330607).

Almost surely, 2^618661213 is an apocalyptic number.

It is an amenable number.

618661213 is a deficient number, since it is larger than the sum of its proper divisors (1).

618661213 is an equidigital number, since it uses as much as digits as its factorization.

618661213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 34.

The square root of 618661213 is about 24872.9011777878. The cubic root of 618661213 is about 852.0876999991.

The spelling of 618661213 in words is "six hundred eighteen million, six hundred sixty-one thousand, two hundred thirteen".