18800521 has 4 divisors (see below), whose sum is σ = 19906452. Its totient is φ = 17694592.

The previous prime is 18800513. The next prime is 18800563. The reversal of 18800521 is 12500881.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9066121 + 9734400 = 3011^2 + 3120^2 .

It is a cyclic number.

It is not a de Polignac number, because 18800521 - 2³ = 18800513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18800581) 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, 552940 + ... + 552973.

It is an arithmetic number, because the mean of its divisors is an integer number (4976613).

Almost surely, 2^18800521 is an apocalyptic number.

It is an amenable number.

18800521 is a deficient number, since it is larger than the sum of its proper divisors (1105931).

18800521 is a wasteful number, since it uses less digits than its factorization.

18800521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1105930.

The product of its (nonzero) digits is 640, while the sum is 25.

The square root of 18800521 is about 4335.9567571644. The cubic root of 18800521 is about 265.9030353044.

It can be divided in two parts, 18800 and 521, that added together give a square (19321 = 139²).

The spelling of 18800521 in words is "eighteen million, eight hundred thousand, five hundred twenty-one".