20342921 has 2 divisors, whose sum is σ = 20342922. Its totient is φ = 20342920.

The previous prime is 20342911. The next prime is 20342923. The reversal of 20342921 is 12924302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14167696 + 6175225 = 3764^2 + 2485^2 .

It is a cyclic number.

It is not a de Polignac number, because 20342921 - 2²² = 16148617 is a prime.

Together with 20342923, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 16.

It is not a weakly prime, because it can be changed into another prime (20342923) 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 as a sum of consecutive naturals, namely, 10171460 + 10171461.

It is an arithmetic number, because the mean of its divisors is an integer number (10171461).

Almost surely, 2^20342921 is an apocalyptic number.

It is an amenable number.

20342921 is a deficient number, since it is larger than the sum of its proper divisors (1).

20342921 is an equidigital number, since it uses as much as digits as its factorization.

20342921 is an odious number, because the sum of its binary digits is odd.

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

The square root of 20342921 is about 4510.3127386025. The cubic root of 20342921 is about 272.9843631327.

The spelling of 20342921 in words is "twenty million, three hundred forty-two thousand, nine hundred twenty-one".