42340021 has 4 divisors (see below), whose sum is σ = 42368544. Its totient is φ = 42311500.

The previous prime is 42340009. The next prime is 42340027. The reversal of 42340021 is 12004324.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 42340021 - 2⁹ = 42339509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 42339977 and 42340004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42340027) 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, 11905 + ... + 15046.

It is an arithmetic number, because the mean of its divisors is an integer number (10592136).

Almost surely, 2^42340021 is an apocalyptic number.

It is an amenable number.

42340021 is a deficient number, since it is larger than the sum of its proper divisors (28523).

42340021 is a wasteful number, since it uses less digits than its factorization.

42340021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28522.

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

The square root of 42340021 is about 6506.9210076656. The cubic root of 42340021 is about 348.5381778328.

Adding to 42340021 its reverse (12004324), we get a palindrome (54344345).

The spelling of 42340021 in words is "forty-two million, three hundred forty thousand, twenty-one".