21023312280 has 64 divisors (see below), whose sum is σ = 66389414400. Its totient is φ = 5311152000.

The previous prime is 21023312279. The next prime is 21023312281. The reversal of 21023312280 is 8221332012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21023312279) and next prime (21023312281).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21023312280.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21023312281) 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, 4608096 + ... + 4612655.

It is an arithmetic number, because the mean of its divisors is an integer number (1037334600).

Almost surely, 2^21023312280 is an apocalyptic number.

21023312280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21023312280 is an abundant number, since it is smaller than the sum of its proper divisors (45366102120).

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

21023312280 is a wasteful number, since it uses less digits than its factorization.

21023312280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9220784 (or 9220780 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

Adding to 21023312280 its reverse (8221332012), we get a palindrome (29244644292).

The spelling of 21023312280 in words is "twenty-one billion, twenty-three million, three hundred twelve thousand, two hundred eighty".