20942321 has 4 divisors (see below), whose sum is σ = 21664500. Its totient is φ = 20220144.

The previous prime is 20942309. The next prime is 20942357. The reversal of 20942321 is 12324902.

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 12503296 + 8439025 = 3536^2 + 2905^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20942321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20942371) 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, 361046 + ... + 361103.

It is an arithmetic number, because the mean of its divisors is an integer number (5416125).

Almost surely, 2^20942321 is an apocalyptic number.

It is an amenable number.

20942321 is a deficient number, since it is larger than the sum of its proper divisors (722179).

20942321 is an equidigital number, since it uses as much as digits as its factorization.

20942321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 722178.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 20942321 is about 4576.2780728448. The cubic root of 20942321 is about 275.6395955715.

The spelling of 20942321 in words is "twenty million, nine hundred forty-two thousand, three hundred twenty-one".