21323440220 has 48 divisors (see below), whose sum is σ = 45125942400. Its totient is φ = 8463587904.

The previous prime is 21323440157. The next prime is 21323440223. The reversal of 21323440220 is 2204432312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21323440223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1386131 + ... + 1401429.

It is an arithmetic number, because the mean of its divisors is an integer number (940123800).

Almost surely, 2^21323440220 is an apocalyptic number.

21323440220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21323440220 is an abundant number, since it is smaller than the sum of its proper divisors (23802502180).

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

21323440220 is a wasteful number, since it uses less digits than its factorization.

21323440220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15842 (or 15840 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 23.

Adding to 21323440220 its reverse (2204432312), we get a palindrome (23527872532).

The spelling of 21323440220 in words is "twenty-one billion, three hundred twenty-three million, four hundred forty thousand, two hundred twenty".