218605454621 has 2 divisors, whose sum is σ = 218605454622. Its totient is φ = 218605454620.

The previous prime is 218605454549. The next prime is 218605454653. The reversal of 218605454621 is 126454506812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 163854134521 + 54751320100 = 404789^2 + 233990^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-218605454621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218605450621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109302727310 + 109302727311.

It is an arithmetic number, because the mean of its divisors is an integer number (109302727311).

Almost surely, 2^218605454621 is an apocalyptic number.

It is an amenable number.

218605454621 is a deficient number, since it is larger than the sum of its proper divisors (1).

218605454621 is an equidigital number, since it uses as much as digits as its factorization.

218605454621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 460800, while the sum is 44.

The spelling of 218605454621 in words is "two hundred eighteen billion, six hundred five million, four hundred fifty-four thousand, six hundred twenty-one".