42139802909 has 2 divisors, whose sum is σ = 42139802910. Its totient is φ = 42139802908.

The previous prime is 42139802891. The next prime is 42139802923. The reversal of 42139802909 is 90920893124.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29018100409 + 13121702500 = 170347^2 + 114550^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42139802909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42139802989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21069901454 + 21069901455.

It is an arithmetic number, because the mean of its divisors is an integer number (21069901455).

Almost surely, 2^42139802909 is an apocalyptic number.

It is an amenable number.

42139802909 is a deficient number, since it is larger than the sum of its proper divisors (1).

42139802909 is an equidigital number, since it uses as much as digits as its factorization.

42139802909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 279936, while the sum is 47.

The spelling of 42139802909 in words is "forty-two billion, one hundred thirty-nine million, eight hundred two thousand, nine hundred nine".