2688000021 has 12 divisors (see below), whose sum is σ = 4437333472. Its totient is φ = 1535999976.

The previous prime is 2688000011. The next prime is 2688000023. The reversal of 2688000021 is 1200008862.

It is not a de Polignac number, because 2688000021 - 2¹¹ = 2687997973 is a prime.

It is a super-2 number, since 2×2688000021² = 14450688225792000882, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2688000023) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21333271 + ... + 21333396.

Almost surely, 2^2688000021 is an apocalyptic number.

2688000021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2688000021 is a deficient number, since it is larger than the sum of its proper divisors (1749333451).

2688000021 is a wasteful number, since it uses less digits than its factorization.

2688000021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42666680 (or 42666677 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 2688000021 is about 51845.9257897860. The cubic root of 2688000021 is about 1390.4106615754.

Adding to 2688000021 its reverse (1200008862), we get a palindrome (3888008883).

The spelling of 2688000021 in words is "two billion, six hundred eighty-eight million, twenty-one", and thus it is an aban number.