42139897 has 2 divisors, whose sum is σ = 42139898. Its totient is φ = 42139896.

The previous prime is 42139879. The next prime is 42139913. The reversal of 42139897 is 79893124.

Together with previous prime (42139879) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23658496 + 18481401 = 4864^2 + 4299^2 .

It is a cyclic number.

It is not a de Polignac number, because 42139897 - 2¹⁵ = 42107129 is a prime.

It is not a weakly prime, because it can be changed into another prime (42139817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21069948 + 21069949.

It is an arithmetic number, because the mean of its divisors is an integer number (21069949).

Almost surely, 2^42139897 is an apocalyptic number.

It is an amenable number.

42139897 is a deficient number, since it is larger than the sum of its proper divisors (1).

42139897 is an equidigital number, since it uses as much as digits as its factorization.

42139897 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108864, while the sum is 43.

The square root of 42139897 is about 6491.5250134310. The cubic root of 42139897 is about 347.9881778033.

The spelling of 42139897 in words is "forty-two million, one hundred thirty-nine thousand, eight hundred ninety-seven".