21505500430 has 64 divisors (see below), whose sum is σ = 39529207872. Its totient is φ = 8422686720.

The previous prime is 21505500371. The next prime is 21505500437. The reversal of 21505500430 is 3400550512.

It is a junction number, because it is equal to n+sod(n) for n = 21505500395 and 21505500404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21505500437) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 70050337 + ... + 70050643.

It is an arithmetic number, because the mean of its divisors is an integer number (617643873).

Almost surely, 2^21505500430 is an apocalyptic number.

21505500430 is a deficient number, since it is larger than the sum of its proper divisors (18023707442).

21505500430 is a wasteful number, since it uses less digits than its factorization.

21505500430 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 949.

The product of its (nonzero) digits is 3000, while the sum is 25.

The spelling of 21505500430 in words is "twenty-one billion, five hundred five million, five hundred thousand, four hundred thirty".