21205339072 has 56 divisors (see below), whose sum is σ = 44979957792. Its totient is φ = 9894297600.

The previous prime is 21205339033. The next prime is 21205339121. The reversal of 21205339072 is 27093350212.

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, 115329 + ... + 236032.

It is an arithmetic number, because the mean of its divisors is an integer number (803213532).

Almost surely, 2^21205339072 is an apocalyptic number.

It is an amenable number.

21205339072 is an abundant number, since it is smaller than the sum of its proper divisors (23774618720).

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

21205339072 is a wasteful number, since it uses less digits than its factorization.

21205339072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351437 (or 351427 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 34.

Adding to 21205339072 its reverse (27093350212), we get a palindrome (48298689284).

The spelling of 21205339072 in words is "twenty-one billion, two hundred five million, three hundred thirty-nine thousand, seventy-two".