20154256139 has 2 divisors, whose sum is σ = 20154256140. Its totient is φ = 20154256138.

The previous prime is 20154256123. The next prime is 20154256141. The reversal of 20154256139 is 93165245102.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20154256139 - 2⁴ = 20154256123 is a prime.

Together with 20154256141, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20154256739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10077128069 + 10077128070.

It is an arithmetic number, because the mean of its divisors is an integer number (10077128070).

Almost surely, 2^20154256139 is an apocalyptic number.

20154256139 is a deficient number, since it is larger than the sum of its proper divisors (1).

20154256139 is an equidigital number, since it uses as much as digits as its factorization.

20154256139 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64800, while the sum is 38.

The spelling of 20154256139 in words is "twenty billion, one hundred fifty-four million, two hundred fifty-six thousand, one hundred thirty-nine".