21059291 has 4 divisors (see below), whose sum is σ = 22973784. Its totient is φ = 19144800.

The previous prime is 21059273. The next prime is 21059309. The reversal of 21059291 is 19295012.

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

It is an interprime number because it is at equal distance from previous prime (21059273) and next prime (21059309).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21059291 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21059221) 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, 957230 + ... + 957251.

It is an arithmetic number, because the mean of its divisors is an integer number (5743446).

Almost surely, 2^21059291 is an apocalyptic number.

21059291 is a deficient number, since it is larger than the sum of its proper divisors (1914493).

21059291 is a wasteful number, since it uses less digits than its factorization.

21059291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1914492.

The product of its (nonzero) digits is 1620, while the sum is 29.

The square root of 21059291 is about 4589.0403136168. The cubic root of 21059291 is about 276.1518234562.

The spelling of 21059291 in words is "twenty-one million, fifty-nine thousand, two hundred ninety-one".