21059513 has 4 divisors (see below), whose sum is σ = 21975168. Its totient is φ = 20143860.

The previous prime is 21059477. The next prime is 21059537. The reversal of 21059513 is 31595012.

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 not a de Polignac number, because 21059513 - 2⁶ = 21059449 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21059593) 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, 457793 + ... + 457838.

It is an arithmetic number, because the mean of its divisors is an integer number (5493792).

Almost surely, 2^21059513 is an apocalyptic number.

21059513 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21059513 is a deficient number, since it is larger than the sum of its proper divisors (915655).

21059513 is an equidigital number, since it uses as much as digits as its factorization.

21059513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 915654.

The product of its (nonzero) digits is 1350, while the sum is 26.

The square root of 21059513 is about 4589.0645016169. The cubic root of 21059513 is about 276.1527938195.

The spelling of 21059513 in words is "twenty-one million, fifty-nine thousand, five hundred thirteen".