21521115100 has 18 divisors (see below), whose sum is σ = 46700819984. Its totient is φ = 8608446000.

The previous prime is 21521115079. The next prime is 21521115137. The reversal of 21521115100 is 151112512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 107605476 + ... + 107605675.

Almost surely, 2^21521115100 is an apocalyptic number.

21521115100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21521115100 is an abundant number, since it is smaller than the sum of its proper divisors (25179704884).

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

21521115100 is a wasteful number, since it uses less digits than its factorization.

21521115100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215211165 (or 215211158 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 19.

Adding to 21521115100 its reverse (151112512), we get a palindrome (21672227612).

The spelling of 21521115100 in words is "twenty-one billion, five hundred twenty-one million, one hundred fifteen thousand, one hundred".