20257321 has 8 divisors (see below), whose sum is σ = 23716224. Its totient is φ = 16939680.

The previous prime is 20257309. The next prime is 20257327. The reversal of 20257321 is 12375202.

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 20257321 - 2²¹ = 18160169 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20257292 and 20257301.

It is not an unprimeable number, because it can be changed into a prime (20257327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35005 + ... + 35578.

It is an arithmetic number, because the mean of its divisors is an integer number (2964528).

Almost surely, 2^20257321 is an apocalyptic number.

It is an amenable number.

20257321 is a deficient number, since it is larger than the sum of its proper divisors (3458903).

20257321 is an equidigital number, since it uses as much as digits as its factorization.

20257321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70631.

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 20257321 is about 4500.8133709364. The cubic root of 20257321 is about 272.6009322261.

The spelling of 20257321 in words is "twenty million, two hundred fifty-seven thousand, three hundred twenty-one".