21114640 has 20 divisors (see below), whose sum is σ = 49091724. Its totient is φ = 8445824.

The previous prime is 21114623. The next prime is 21114647. The reversal of 21114640 is 4641112.

It can be written as a sum of positive squares in 2 ways, for example, as 4857616 + 16257024 = 2204^2 + 4032^2 .

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21114647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131887 + ... + 132046.

Almost surely, 2^21114640 is an apocalyptic number.

21114640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21114640 is an abundant number, since it is smaller than the sum of its proper divisors (27977084).

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

21114640 is a wasteful number, since it uses less digits than its factorization.

21114640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263946 (or 263940 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 21114640 is about 4595.0669200785. The cubic root of 21114640 is about 276.3935434666.

Adding to 21114640 its reverse (4641112), we get a palindrome (25755752).

The spelling of 21114640 in words is "twenty-one million, one hundred fourteen thousand, six hundred forty".