42104021 has 4 divisors (see below), whose sum is σ = 42117792. Its totient is φ = 42090252.

The previous prime is 42104017. The next prime is 42104033. The reversal of 42104021 is 12040124.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 42104021 - 2² = 42104017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 42103987 and 42104005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42104011) 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, 11 + ... + 9176.

It is an arithmetic number, because the mean of its divisors is an integer number (10529448).

Almost surely, 2^42104021 is an apocalyptic number.

It is an amenable number.

42104021 is a deficient number, since it is larger than the sum of its proper divisors (13771).

42104021 is an equidigital number, since it uses as much as digits as its factorization.

42104021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13770.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 42104021 is about 6488.7611298306. The cubic root of 42104021 is about 347.8893959733.

Adding to 42104021 its reverse (12040124), we get a palindrome (54144145).

The spelling of 42104021 in words is "forty-two million, one hundred four thousand, twenty-one".