20123456 has 28 divisors (see below), whose sum is σ = 40911780. Its totient is φ = 9815040.

The previous prime is 20123443. The next prime is 20123479. The reversal of 20123456 is 65432102.

It can be written as a sum of positive squares in 2 ways, for example, as 9985600 + 10137856 = 3160^2 + 3184^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1211 + ... + 6458.

It is an arithmetic number, because the mean of its divisors is an integer number (1461135).

Almost surely, 2^20123456 is an apocalyptic number.

It is an amenable number.

20123456 is an abundant number, since it is smaller than the sum of its proper divisors (20788324).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20123456 is an equidigital number, since it uses as much as digits as its factorization.

20123456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7722 (or 7712 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 20123456 is about 4485.9175204188. The cubic root of 20123456 is about 271.9991349453. Note that the first 3 decimals are identical.

Adding to 20123456 its reverse (65432102), we get a palindrome (85555558).

The spelling of 20123456 in words is "twenty million, one hundred twenty-three thousand, four hundred fifty-six".