18212993 has 2 divisors, whose sum is σ = 18212994. Its totient is φ = 18212992.

The previous prime is 18212981. The next prime is 18213007. The reversal of 18212993 is 39921281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9314704 + 8898289 = 3052^2 + 2983^2 .

It is a cyclic number.

It is not a de Polignac number, because 18212993 - 2¹⁰ = 18211969 is a prime.

It is a super-2 number, since 2×18212993² = 663426228036098, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18212093) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9106496 + 9106497.

It is an arithmetic number, because the mean of its divisors is an integer number (9106497).

Almost surely, 2^18212993 is an apocalyptic number.

It is an amenable number.

18212993 is a deficient number, since it is larger than the sum of its proper divisors (1).

18212993 is an equidigital number, since it uses as much as digits as its factorization.

18212993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 35.

The square root of 18212993 is about 4267.6683329425. The cubic root of 18212993 is about 263.1037916755.

The spelling of 18212993 in words is "eighteen million, two hundred twelve thousand, nine hundred ninety-three".