20455139 has 2 divisors, whose sum is σ = 20455140. Its totient is φ = 20455138.

The previous prime is 20455129. The next prime is 20455157. The reversal of 20455139 is 93155402.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20455139 - 2⁸ = 20454883 is a prime.

It is not a weakly prime, because it can be changed into another prime (20455109) 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, 10227569 + 10227570.

It is an arithmetic number, because the mean of its divisors is an integer number (10227570).

Almost surely, 2^20455139 is an apocalyptic number.

20455139 is a deficient number, since it is larger than the sum of its proper divisors (1).

20455139 is an equidigital number, since it uses as much as digits as its factorization.

20455139 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 20455139 is about 4522.7357871094. The cubic root of 20455139 is about 273.4853990581.

The spelling of 20455139 in words is "twenty million, four hundred fifty-five thousand, one hundred thirty-nine".