18836521 has 4 divisors (see below), whose sum is σ = 20548944. Its totient is φ = 17124100.

The previous prime is 18836509. The next prime is 18836533. The reversal of 18836521 is 12563881.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12563881 = 11 ⋅1142171.

It is an interprime number because it is at equal distance from previous prime (18836509) and next prime (18836533).

It is a cyclic number.

It is not a de Polignac number, because 18836521 - 2⁹ = 18836009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18836501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 856195 + ... + 856216.

It is an arithmetic number, because the mean of its divisors is an integer number (5137236).

Almost surely, 2^18836521 is an apocalyptic number.

18836521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18836521 is a deficient number, since it is larger than the sum of its proper divisors (1712423).

18836521 is a wasteful number, since it uses less digits than its factorization.

18836521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1712422.

The product of its digits is 11520, while the sum is 34.

The square root of 18836521 is about 4340.1061046938. The cubic root of 18836521 is about 266.0726477284.

The spelling of 18836521 in words is "eighteen million, eight hundred thirty-six thousand, five hundred twenty-one".