42123391 has 4 divisors (see below), whose sum is σ = 42250984. Its totient is φ = 41995800.

The previous prime is 42123379. The next prime is 42123401. The reversal of 42123391 is 19332124.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42123391 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42123091) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63300 + ... + 63961.

It is an arithmetic number, because the mean of its divisors is an integer number (10562746).

Almost surely, 2^42123391 is an apocalyptic number.

42123391 is a deficient number, since it is larger than the sum of its proper divisors (127593).

42123391 is a wasteful number, since it uses less digits than its factorization.

42123391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127592.

The product of its digits is 1296, while the sum is 25.

The square root of 42123391 is about 6490.2535389613. The cubic root of 42123391 is about 347.9427367575.

The spelling of 42123391 in words is "forty-two million, one hundred twenty-three thousand, three hundred ninety-one".