218898201581 has 2 divisors, whose sum is σ = 218898201582. Its totient is φ = 218898201580.

The previous prime is 218898201559. The next prime is 218898201629. The reversal of 218898201581 is 185102898812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 170623520356 + 48274681225 = 413066^2 + 219715^2 .

It is a cyclic number.

It is not a de Polignac number, because 218898201581 - 2¹⁰ = 218898200557 is a prime.

It is a super-2 number, since 2×218898201581² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218898201541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109449100790 + 109449100791.

It is an arithmetic number, because the mean of its divisors is an integer number (109449100791).

Almost surely, 2^218898201581 is an apocalyptic number.

It is an amenable number.

218898201581 is a deficient number, since it is larger than the sum of its proper divisors (1).

218898201581 is an equidigital number, since it uses as much as digits as its factorization.

218898201581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 737280, while the sum is 53.

The spelling of 218898201581 in words is "two hundred eighteen billion, eight hundred ninety-eight million, two hundred one thousand, five hundred eighty-one".