20868440 has 32 divisors (see below), whose sum is σ = 47267280. Its totient is φ = 8291712.

The previous prime is 20868439. The next prime is 20868443. The reversal of 20868440 is 4486802.

It is a junction number, because it is equal to n+sod(n) for n = 20868397 and 20868406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20868443) 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, 4619 + ... + 7941.

Almost surely, 2^20868440 is an apocalyptic number.

20868440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20868440 is an abundant number, since it is smaller than the sum of its proper divisors (26398840).

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

20868440 is a wasteful number, since it uses less digits than its factorization.

20868440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3491 (or 3487 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 32.

The square root of 20868440 is about 4568.1987697560. The cubic root of 20868440 is about 275.3150768843.

The spelling of 20868440 in words is "twenty million, eight hundred sixty-eight thousand, four hundred forty".