21012303400 has 72 divisors (see below), whose sum is σ = 53698652910. Its totient is φ = 7640828800.

The previous prime is 21012303383. The next prime is 21012303401. The reversal of 21012303400 is 430321012.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 19082107044 + 1930196356 = 138138^2 + 43934^2 .

It is not an unprimeable number, because it can be changed into a prime (21012303401) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 409939 + ... + 458338.

Almost surely, 2^21012303400 is an apocalyptic number.

21012303400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21012303400 is an abundant number, since it is smaller than the sum of its proper divisors (32686349510).

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

21012303400 is a wasteful number, since it uses less digits than its factorization.

21012303400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 868315 (or 868295 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

Adding to 21012303400 its reverse (430321012), we get a palindrome (21442624412).

The spelling of 21012303400 in words is "twenty-one billion, twelve million, three hundred three thousand, four hundred".