20423501 has 4 divisors (see below), whose sum is σ = 23341152. Its totient is φ = 17505852.

The previous prime is 20423489. The next prime is 20423509. The reversal of 20423501 is 10532402.

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: 10532402 = 2 ⋅5266201.

It is not a de Polignac number, because 20423501 - 2¹⁴ = 20407117 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20423501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20423509) 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, 1458815 + ... + 1458828.

It is an arithmetic number, because the mean of its divisors is an integer number (5835288).

Almost surely, 2^20423501 is an apocalyptic number.

It is an amenable number.

20423501 is a deficient number, since it is larger than the sum of its proper divisors (2917651).

20423501 is an equidigital number, since it uses as much as digits as its factorization.

20423501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2917650.

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 20423501 is about 4519.2367718454. The cubic root of 20423501 is about 273.3443261823.

Adding to 20423501 its reverse (10532402), we get a palindrome (30955903).

The spelling of 20423501 in words is "twenty million, four hundred twenty-three thousand, five hundred one".