21676240 has 20 divisors (see below), whose sum is σ = 50397444. Its totient is φ = 8670464.

The previous prime is 21676231. The next prime is 21676261. The reversal of 21676240 is 4267612.

It can be written as a sum of positive squares in 2 ways, for example, as 2944656 + 18731584 = 1716^2 + 4328^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 21676199 and 21676208.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 135397 + ... + 135556.

Almost surely, 2^21676240 is an apocalyptic number.

21676240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21676240 is an abundant number, since it is smaller than the sum of its proper divisors (28721204).

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

21676240 is a wasteful number, since it uses less digits than its factorization.

21676240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 270966 (or 270960 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 21676240 is about 4655.7749086484. The cubic root of 21676240 is about 278.8226070522.

The spelling of 21676240 in words is "twenty-one million, six hundred seventy-six thousand, two hundred forty".