42640039 has 4 divisors (see below), whose sum is σ = 45920056. Its totient is φ = 39360024.

The previous prime is 42640033. The next prime is 42640051. The reversal of 42640039 is 93004624.

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 42640039 - 2⁵ = 42640007 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 42639989 and 42640016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42640033) 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, 1639989 + ... + 1640014.

It is an arithmetic number, because the mean of its divisors is an integer number (11480014).

Almost surely, 2^42640039 is an apocalyptic number.

42640039 is a deficient number, since it is larger than the sum of its proper divisors (3280017).

42640039 is a wasteful number, since it uses less digits than its factorization.

42640039 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3280016.

The product of its (nonzero) digits is 5184, while the sum is 28.

The square root of 42640039 is about 6529.9340731741. The cubic root of 42640039 is about 349.3594788628.

The spelling of 42640039 in words is "forty-two million, six hundred forty thousand, thirty-nine".