21693760 has 56 divisors (see below), whose sum is σ = 56363616. Its totient is φ = 7887360.

The previous prime is 21693739. The next prime is 21693767. The reversal of 21693760 is 6739612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21693767) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 439 + ... + 6601.

Almost surely, 2^21693760 is an apocalyptic number.

21693760 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 21693760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28181808).

21693760 is an abundant number, since it is smaller than the sum of its proper divisors (34669856).

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

21693760 is a wasteful number, since it uses less digits than its factorization.

21693760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6191 (or 6181 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 34.

The square root of 21693760 is about 4657.6560628711. The cubic root of 21693760 is about 278.8977070474.

It can be divided in two parts, 2169 and 3760, that added together give a square (5929 = 77²).

The spelling of 21693760 in words is "twenty-one million, six hundred ninety-three thousand, seven hundred sixty".