21030688 has 24 divisors (see below), whose sum is σ = 47319552. Its totient is φ = 9013056.

The previous prime is 21030677. The next prime is 21030703. The reversal of 21030688 is 88603012.

It is a Harshad number since it is a multiple of its sum of digits (28).

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, 46720 + ... + 47167.

It is an arithmetic number, because the mean of its divisors is an integer number (1971648).

Almost surely, 2^21030688 is an apocalyptic number.

21030688 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21030688 is an abundant number, since it is smaller than the sum of its proper divisors (26288864).

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

21030688 is an equidigital number, since it uses as much as digits as its factorization.

21030688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93904 (or 93896 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 21030688 is about 4585.9228078981. The cubic root of 21030688 is about 276.0267424903.

The spelling of 21030688 in words is "twenty-one million, thirty thousand, six hundred eighty-eight".