42400123 has 4 divisors (see below), whose sum is σ = 42428880. Its totient is φ = 42371368.

The previous prime is 42400121. The next prime is 42400139. The reversal of 42400123 is 32100424.

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

It is a cyclic number.

It is not a de Polignac number, because 42400123 - 2¹ = 42400121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 42400097 and 42400106.

It is not an unprimeable number, because it can be changed into a prime (42400121) 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, 12040 + ... + 15157.

It is an arithmetic number, because the mean of its divisors is an integer number (10607220).

Almost surely, 2^42400123 is an apocalyptic number.

42400123 is a deficient number, since it is larger than the sum of its proper divisors (28757).

42400123 is a wasteful number, since it uses less digits than its factorization.

42400123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28756.

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 42400123 is about 6511.5376832205. The cubic root of 42400123 is about 348.7030174416.

Adding to 42400123 its reverse (32100424), we get a palindrome (74500547).

The spelling of 42400123 in words is "forty-two million, four hundred thousand, one hundred twenty-three".