18353521 has 2 divisors, whose sum is σ = 18353522. Its totient is φ = 18353520.

The previous prime is 18353513. The next prime is 18353539. The reversal of 18353521 is 12535381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17969121 + 384400 = 4239^2 + 620^2 .

It is a cyclic number.

It is not a de Polignac number, because 18353521 - 2³ = 18353513 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18353521.

It is not a weakly prime, because it can be changed into another prime (18353501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9176760 + 9176761.

It is an arithmetic number, because the mean of its divisors is an integer number (9176761).

Almost surely, 2^18353521 is an apocalyptic number.

It is an amenable number.

18353521 is a deficient number, since it is larger than the sum of its proper divisors (1).

18353521 is an equidigital number, since it uses as much as digits as its factorization.

18353521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3600, while the sum is 28.

The square root of 18353521 is about 4284.1009558599. The cubic root of 18353521 is about 263.7787450234.

It can be divided in two parts, 1835 and 3521, that added together give a triangular number (5356 = T₁₀₃).

The spelling of 18353521 in words is "eighteen million, three hundred fifty-three thousand, five hundred twenty-one".