21205728300 has 36 divisors (see below), whose sum is σ = 61355241416. Its totient is φ = 5654860800.

The previous prime is 21205728289. The next prime is 21205728361. The reversal of 21205728300 is 382750212.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35342581 + ... + 35343180.

Almost surely, 2^21205728300 is an apocalyptic number.

21205728300 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21205728300 is an abundant number, since it is smaller than the sum of its proper divisors (40149513116).

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

21205728300 is a wasteful number, since it uses less digits than its factorization.

21205728300 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70685778 (or 70685771 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 30.

The spelling of 21205728300 in words is "twenty-one billion, two hundred five million, seven hundred twenty-eight thousand, three hundred".