21000421104 has 40 divisors (see below), whose sum is σ = 58424250192. Its totient is φ = 6461667840.

The previous prime is 21000421069. The next prime is 21000421129. The reversal of 21000421104 is 40112400012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16826637 + ... + 16827884.

Almost surely, 2^21000421104 is an apocalyptic number.

21000421104 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21000421104 is an abundant number, since it is smaller than the sum of its proper divisors (37423829088).

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

21000421104 is a wasteful number, since it uses less digits than its factorization.

21000421104 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33654545 (or 33654539 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21000421104 its reverse (40112400012), we get a palindrome (61112821116).

The spelling of 21000421104 in words is "twenty-one billion, four hundred twenty-one thousand, one hundred four".