18834721 has 2 divisors, whose sum is σ = 18834722. Its totient is φ = 18834720.

The previous prime is 18834713. The next prime is 18834743. The reversal of 18834721 is 12743881.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18584721 + 250000 = 4311^2 + 500^2 .

It is a cyclic number.

It is not a de Polignac number, because 18834721 - 2³ = 18834713 is a prime.

It is not a weakly prime, because it can be changed into another prime (18834121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9417360 + 9417361.

It is an arithmetic number, because the mean of its divisors is an integer number (9417361).

Almost surely, 2^18834721 is an apocalyptic number.

It is an amenable number.

18834721 is a deficient number, since it is larger than the sum of its proper divisors (1).

18834721 is an equidigital number, since it uses as much as digits as its factorization.

18834721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10752, while the sum is 34.

The square root of 18834721 is about 4339.8987315374. The cubic root of 18834721 is about 266.0641722422.

The spelling of 18834721 in words is "eighteen million, eight hundred thirty-four thousand, seven hundred twenty-one".