20400023 has 12 divisors (see below), whose sum is σ = 23808672. Its totient is φ = 17428320.

The previous prime is 20400019. The next prime is 20400031. The reversal of 20400023 is 32000402.

It is not a de Polignac number, because 20400023 - 2² = 20400019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20399977 and 20400013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20400013) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21938 + ... + 22848.

It is an arithmetic number, because the mean of its divisors is an integer number (1984056).

Almost surely, 2^20400023 is an apocalyptic number.

20400023 is a deficient number, since it is larger than the sum of its proper divisors (3408649).

20400023 is an equidigital number, since it uses as much as digits as its factorization.

20400023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1382 (or 1375 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 11.

The square root of 20400023 is about 4516.6384623966. The cubic root of 20400023 is about 273.2395442974.

Adding to 20400023 its reverse (32000402), we get a palindrome (52400425).

The spelling of 20400023 in words is "twenty million, four hundred thousand, twenty-three".