21305205264 has 40 divisors (see below), whose sum is σ = 62901083200. Its totient is φ = 6087201408.

The previous prime is 21305205211. The next prime is 21305205269. The reversal of 21305205264 is 46250250312.

It is not an unprimeable number, because it can be changed into a prime (21305205269) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31703839 + ... + 31704510.

It is an arithmetic number, because the mean of its divisors is an integer number (1572527080).

Almost surely, 2^21305205264 is an apocalyptic number.

21305205264 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21305205264 is an abundant number, since it is smaller than the sum of its proper divisors (41595877936).

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

21305205264 is a wasteful number, since it uses less digits than its factorization.

21305205264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63408367 (or 63408361 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 30.

Adding to 21305205264 its reverse (46250250312), we get a palindrome (67555455576).

The spelling of 21305205264 in words is "twenty-one billion, three hundred five million, two hundred five thousand, two hundred sixty-four".