42021823 has 4 divisors (see below), whose sum is σ = 42064480. Its totient is φ = 41979168.

The previous prime is 42021817. The next prime is 42021829. The reversal of 42021823 is 32812024.

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

It is an interprime number because it is at equal distance from previous prime (42021817) and next prime (42021829).

It is a cyclic number.

It is not a de Polignac number, because 42021823 - 2²¹ = 39924671 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 42021794 and 42021803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42021829) 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, 19815 + ... + 21832.

It is an arithmetic number, because the mean of its divisors is an integer number (10516120).

Almost surely, 2^42021823 is an apocalyptic number.

42021823 is a deficient number, since it is larger than the sum of its proper divisors (42657).

42021823 is a wasteful number, since it uses less digits than its factorization.

42021823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42656.

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 42021823 is about 6482.4241607596. The cubic root of 42021823 is about 347.6628582941.

Adding to 42021823 its reverse (32812024), we get a palindrome (74833847).

The spelling of 42021823 in words is "forty-two million, twenty-one thousand, eight hundred twenty-three".