18411521 has 2 divisors, whose sum is σ = 18411522. Its totient is φ = 18411520.

The previous prime is 18411499. The next prime is 18411529. The reversal of 18411521 is 12511481.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14554225 + 3857296 = 3815^2 + 1964^2 .

It is a cyclic number.

It is not a de Polignac number, because 18411521 - 2¹⁴ = 18395137 is a prime.

It is not a weakly prime, because it can be changed into another prime (18411529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9205760 + 9205761.

It is an arithmetic number, because the mean of its divisors is an integer number (9205761).

Almost surely, 2^18411521 is an apocalyptic number.

It is an amenable number.

18411521 is a deficient number, since it is larger than the sum of its proper divisors (1).

18411521 is an equidigital number, since it uses as much as digits as its factorization.

18411521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 320, while the sum is 23.

The square root of 18411521 is about 4290.8648312432. The cubic root of 18411521 is about 264.0563135532.

It can be divided in two parts, 1841 and 1521, that multiplied together give a triangular number (2800161 = T₂₃₆₆).

The spelling of 18411521 in words is "eighteen million, four hundred eleven thousand, five hundred twenty-one".