21961227288 has 384 divisors, whose sum is σ = 76802584320. Its totient is φ = 5141283840.

The previous prime is 21961227221. The next prime is 21961227361. The reversal of 21961227288 is 88272216912.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 7229706 + ... + 7232742.

It is an arithmetic number, because the mean of its divisors is an integer number (200006730).

Almost surely, 2^21961227288 is an apocalyptic number.

21961227288 is a gapful number since it is divisible by the number (28) 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 21961227288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38401292160).

21961227288 is an abundant number, since it is smaller than the sum of its proper divisors (54841357032).

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

21961227288 is a wasteful number, since it uses less digits than its factorization.

21961227288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3127 (or 3116 counting only the distinct ones).

The product of its digits is 387072, while the sum is 48.

The spelling of 21961227288 in words is "twenty-one billion, nine hundred sixty-one million, two hundred twenty-seven thousand, two hundred eighty-eight".