20421423 has 32 divisors (see below), whose sum is σ = 34156800. Its totient is φ = 11944800.

The previous prime is 20421419. The next prime is 20421433. The reversal of 20421423 is 32412402.

It is not a de Polignac number, because 20421423 - 2² = 20421419 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20421396 and 20421405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421413) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7428 + ... + 9798.

It is an arithmetic number, because the mean of its divisors is an integer number (1067400).

Almost surely, 2^20421423 is an apocalyptic number.

20421423 is a deficient number, since it is larger than the sum of its proper divisors (13735377).

20421423 is a wasteful number, since it uses less digits than its factorization.

20421423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2420 (or 2414 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 20421423 is about 4519.0068599196. The cubic root of 20421423 is about 273.3350553464.

Adding to 20421423 its reverse (32412402), we get a palindrome (52833825).

The spelling of 20421423 in words is "twenty million, four hundred twenty-one thousand, four hundred twenty-three".