20842123 has 4 divisors (see below), whose sum is σ = 20861208. Its totient is φ = 20823040.

The previous prime is 20842093. The next prime is 20842127. The reversal of 20842123 is 32124802.

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 20842123 - 2¹³ = 20833931 is a prime.

It is a super-2 number, since 2×20842123² = 868788182294258, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20842094 and 20842103.

It is not an unprimeable number, because it can be changed into a prime (20842127) 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, 7798 + ... + 10123.

It is an arithmetic number, because the mean of its divisors is an integer number (5215302).

Almost surely, 2^20842123 is an apocalyptic number.

20842123 is a deficient number, since it is larger than the sum of its proper divisors (19085).

20842123 is a wasteful number, since it uses less digits than its factorization.

20842123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19084.

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

The square root of 20842123 is about 4565.3174040805. The cubic root of 20842123 is about 275.1992957535.

Adding to 20842123 its reverse (32124802), we get a palindrome (52966925).

The spelling of 20842123 in words is "twenty million, eight hundred forty-two thousand, one hundred twenty-three".