21996760 has 32 divisors (see below), whose sum is σ = 50126400. Its totient is φ = 8686080.

The previous prime is 21996757. The next prime is 21996797. The reversal of 21996760 is 6769912.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 321 + ... + 6640.

It is an arithmetic number, because the mean of its divisors is an integer number (1566450).

Almost surely, 2^21996760 is an apocalyptic number.

21996760 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 21996760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25063200).

21996760 is an abundant number, since it is smaller than the sum of its proper divisors (28129640).

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

21996760 is a wasteful number, since it uses less digits than its factorization.

21996760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7051 (or 7047 counting only the distinct ones).

The product of its (nonzero) digits is 40824, while the sum is 40.

The square root of 21996760 is about 4690.0703619455. The cubic root of 21996760 is about 280.1901769244.

The spelling of 21996760 in words is "twenty-one million, nine hundred ninety-six thousand, seven hundred sixty".