21040350400 has 84 divisors (see below), whose sum is σ = 52150856328. Its totient is φ = 8354621440.

The previous prime is 21040350391. The next prime is 21040350433. The reversal of 21040350400 is 405304012.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 171207 + ... + 267193.

Almost surely, 2^21040350400 is an apocalyptic number.

21040350400 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 21040350400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26075428164).

21040350400 is an abundant number, since it is smaller than the sum of its proper divisors (31110505928).

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

21040350400 is a wasteful number, since it uses less digits than its factorization.

21040350400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96146 (or 96131 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

Adding to 21040350400 its reverse (405304012), we get a palindrome (21445654412).

The spelling of 21040350400 in words is "twenty-one billion, forty million, three hundred fifty thousand, four hundred".