18347621 has 2 divisors, whose sum is σ = 18347622. Its totient is φ = 18347620.

The previous prime is 18347603. The next prime is 18347653. The reversal of 18347621 is 12674381.

It is an a-pointer prime, because the next prime (18347653) can be obtained adding 18347621 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14145121 + 4202500 = 3761^2 + 2050^2 .

It is a cyclic number.

It is not a de Polignac number, because 18347621 - 2¹⁰ = 18346597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18347221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9173810 + 9173811.

It is an arithmetic number, because the mean of its divisors is an integer number (9173811).

Almost surely, 2^18347621 is an apocalyptic number.

It is an amenable number.

18347621 is a deficient number, since it is larger than the sum of its proper divisors (1).

18347621 is an equidigital number, since it uses as much as digits as its factorization.

18347621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 32.

The square root of 18347621 is about 4283.4123079620. The cubic root of 18347621 is about 263.7504768528.

The spelling of 18347621 in words is "eighteen million, three hundred forty-seven thousand, six hundred twenty-one".