21766940 has 24 divisors (see below), whose sum is σ = 49227360. Its totient is φ = 8036928.

The previous prime is 21766939. The next prime is 21766957. The reversal of 21766940 is 4966712.

It is a self number, because there is not a number n which added to its sum of digits gives 21766940.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41600 + ... + 42119.

It is an arithmetic number, because the mean of its divisors is an integer number (2051140).

Almost surely, 2^21766940 is an apocalyptic number.

21766940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21766940 is an abundant number, since it is smaller than the sum of its proper divisors (27460420).

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

21766940 is a wasteful number, since it uses less digits than its factorization.

21766940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83741 (or 83739 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 21766940 is about 4665.5053316870. The cubic root of 21766940 is about 279.2109588395.

The spelling of 21766940 in words is "twenty-one million, seven hundred sixty-six thousand, nine hundred forty".