18442121 has 2 divisors, whose sum is σ = 18442122. Its totient is φ = 18442120.

The previous prime is 18442111. The next prime is 18442129. The reversal of 18442121 is 12124481.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11868025 + 6574096 = 3445^2 + 2564^2 .

It is an emirp because it is prime and its reverse (12124481) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18442121 is a prime.

It is a super-2 number, since 2×18442121² = 680223653957282, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18442129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9221060 + 9221061.

It is an arithmetic number, because the mean of its divisors is an integer number (9221061).

Almost surely, 2^18442121 is an apocalyptic number.

It is an amenable number.

18442121 is a deficient number, since it is larger than the sum of its proper divisors (1).

18442121 is an equidigital number, since it uses as much as digits as its factorization.

18442121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 512, while the sum is 23.

The square root of 18442121 is about 4294.4290656617. The cubic root of 18442121 is about 264.2025200314.

The spelling of 18442121 in words is "eighteen million, four hundred forty-two thousand, one hundred twenty-one".