21641359780 has 48 divisors (see below), whose sum is σ = 46947124224. Its totient is φ = 8371186560.

The previous prime is 21641359769. The next prime is 21641359781. The reversal of 21641359780 is 8795314612.

It is a self number, because there is not a number n which added to its sum of digits gives 21641359780.

It is not an unprimeable number, because it can be changed into a prime (21641359781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 888849 + ... + 912871.

It is an arithmetic number, because the mean of its divisors is an integer number (978065088).

It is a 2-persistent number, because it is pandigital, and so is 2⋅21641359780 = 43282719560, but 3⋅21641359780 = 64924079340 is not.

Almost surely, 2^21641359780 is an apocalyptic number.

21641359780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

21641359780 is the 120115-th pentagonal number.

It is an amenable number.

21641359780 is an abundant number, since it is smaller than the sum of its proper divisors (25305764444).

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

21641359780 is a wasteful number, since it uses less digits than its factorization.

21641359780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25516 (or 25514 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 46.

The spelling of 21641359780 in words is "twenty-one billion, six hundred forty-one million, three hundred fifty-nine thousand, seven hundred eighty".