21941680 has 20 divisors (see below), whose sum is σ = 51014592. Its totient is φ = 8776640.

The previous prime is 21941677. The next prime is 21941681. The reversal of 21941680 is 8614912.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (21941681) 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 3 ways as a sum of consecutive naturals, for example, 137056 + ... + 137215.

Almost surely, 2^21941680 is an apocalyptic number.

21941680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21941680 is an abundant number, since it is smaller than the sum of its proper divisors (29072912).

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

21941680 is a wasteful number, since it uses less digits than its factorization.

21941680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274284 (or 274278 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 21941680 is about 4684.1947013334. The cubic root of 21941680 is about 279.9561155713.

The spelling of 21941680 in words is "twenty-one million, nine hundred forty-one thousand, six hundred eighty".