20456400400 has 60 divisors (see below), whose sum is σ = 49222393092. Its totient is φ = 8169925120.

The previous prime is 20456400389. The next prime is 20456400421. The reversal of 20456400400 is 400465402.

It can be written as a sum of positive squares in 6 ways, for example, as 1547950336 + 18908450064 = 39344^2 + 137508^2 .

It is a Harshad number since it is a multiple of its sum of digits (25).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 222042 + ... + 300358.

Almost surely, 2^20456400400 is an apocalyptic number.

20456400400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20456400400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24611196546).

20456400400 is an abundant number, since it is smaller than the sum of its proper divisors (28765992692).

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

20456400400 is a wasteful number, since it uses less digits than its factorization.

20456400400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78988 (or 78977 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 25.

Adding to 20456400400 its reverse (400465402), we get a palindrome (20856865802).

The spelling of 20456400400 in words is "twenty billion, four hundred fifty-six million, four hundred thousand, four hundred".