21294623220 has 96 divisors (see below), whose sum is σ = 64417366272. Its totient is φ = 5224946688.

The previous prime is 21294623171. The next prime is 21294623221. The reversal of 21294623220 is 2232649212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21294623221) 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 31 ways as a sum of consecutive naturals, for example, 200529 + ... + 287751.

It is an arithmetic number, because the mean of its divisors is an integer number (671014232).

Almost surely, 2^21294623220 is an apocalyptic number.

21294623220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21294623220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32208683136).

21294623220 is an abundant number, since it is smaller than the sum of its proper divisors (43122743052).

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

21294623220 is a wasteful number, since it uses less digits than its factorization.

21294623220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87561 (or 87559 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 33.

The spelling of 21294623220 in words is "twenty-one billion, two hundred ninety-four million, six hundred twenty-three thousand, two hundred twenty".