20921259 has 8 divisors (see below), whose sum is σ = 28062720. Its totient is φ = 13863656.

The previous prime is 20921227. The next prime is 20921269. The reversal of 20921259 is 95212902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20921259 - 2⁵ = 20921227 is a prime.

It is a super-3 number, since 3×20921259³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (20921269) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20379 + ... + 21380.

It is an arithmetic number, because the mean of its divisors is an integer number (3507840).

Almost surely, 2^20921259 is an apocalyptic number.

20921259 is a deficient number, since it is larger than the sum of its proper divisors (7141461).

20921259 is a wasteful number, since it uses less digits than its factorization.

20921259 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41929.

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 20921259 is about 4573.9762789066. The cubic root of 20921259 is about 275.5471596459.

The spelling of 20921259 in words is "twenty million, nine hundred twenty-one thousand, two hundred fifty-nine".