21913661440 has 312 divisors, whose sum is σ = 59612132160. Its totient is φ = 7720796160.

The previous prime is 21913661423. The next prime is 21913661443. The reversal of 21913661440 is 4416631912.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a self number, because there is not a number n which added to its sum of digits gives 21913661440.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21913661443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 91688841 + ... + 91689079.

Almost surely, 2^21913661440 is an apocalyptic number.

21913661440 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 21913661440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29806066080).

21913661440 is an abundant number, since it is smaller than the sum of its proper divisors (37698470720).

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

21913661440 is a wasteful number, since it uses less digits than its factorization.

21913661440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 327 (or 294 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 37.

The spelling of 21913661440 in words is "twenty-one billion, nine hundred thirteen million, six hundred sixty-one thousand, four hundred forty".