20423237 has 4 divisors (see below), whose sum is σ = 20898240. Its totient is φ = 19948236.

The previous prime is 20423231. The next prime is 20423257. The reversal of 20423237 is 73232402.

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 an emirpimes, since its reverse is a distinct semiprime: 73232402 = 2 ⋅36616201.

It is a cyclic number.

It is not a de Polignac number, because 20423237 - 2¹² = 20419141 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20423231) 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, 237437 + ... + 237522.

It is an arithmetic number, because the mean of its divisors is an integer number (5224560).

Almost surely, 2^20423237 is an apocalyptic number.

It is an amenable number.

20423237 is a deficient number, since it is larger than the sum of its proper divisors (475003).

20423237 is an equidigital number, since it uses as much as digits as its factorization.

20423237 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 475002.

The product of its (nonzero) digits is 2016, while the sum is 23.

The square root of 20423237 is about 4519.2075632792. The cubic root of 20423237 is about 273.3431484016.

Adding to 20423237 its reverse (73232402), we get a palindrome (93655639).

The spelling of 20423237 in words is "twenty million, four hundred twenty-three thousand, two hundred thirty-seven".