20920457 has 2 divisors, whose sum is σ = 20920458. Its totient is φ = 20920456.

The previous prime is 20920441. The next prime is 20920469. The reversal of 20920457 is 75402902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11806096 + 9114361 = 3436^2 + 3019^2 .

It is a cyclic number.

It is not a de Polignac number, because 20920457 - 2⁴ = 20920441 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20920477) 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 as a sum of consecutive naturals, namely, 10460228 + 10460229.

It is an arithmetic number, because the mean of its divisors is an integer number (10460229).

Almost surely, 2^20920457 is an apocalyptic number.

It is an amenable number.

20920457 is a deficient number, since it is larger than the sum of its proper divisors (1).

20920457 is an equidigital number, since it uses as much as digits as its factorization.

20920457 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 20920457 is about 4573.8886081758. Note that the first 3 decimals coincide. The cubic root of 20920457 is about 275.5436386397.

The spelling of 20920457 in words is "twenty million, nine hundred twenty thousand, four hundred fifty-seven".