18421513 has 4 divisors (see below), whose sum is σ = 20096208. Its totient is φ = 16746820.

The previous prime is 18421493. The next prime is 18421519. The reversal of 18421513 is 31512481.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18421513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18421519) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 837331 + ... + 837352.

It is an arithmetic number, because the mean of its divisors is an integer number (5024052).

Almost surely, 2^18421513 is an apocalyptic number.

It is an amenable number.

18421513 is a deficient number, since it is larger than the sum of its proper divisors (1674695).

18421513 is a wasteful number, since it uses less digits than its factorization.

18421513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1674694.

The product of its digits is 960, while the sum is 25.

The square root of 18421513 is about 4292.0290073577. The cubic root of 18421513 is about 264.1040730246.

Adding to 18421513 its reverse (31512481), we get a palindrome (49933994).

The spelling of 18421513 in words is "eighteen million, four hundred twenty-one thousand, five hundred thirteen".