21026668 has 24 divisors (see below), whose sum is σ = 39795840. Its totient is φ = 9663360.

The previous prime is 21026657. The next prime is 21026689. The reversal of 21026668 is 86662012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13893 + ... + 15331.

It is an arithmetic number, because the mean of its divisors is an integer number (1658160).

Almost surely, 2^21026668 is an apocalyptic number.

It is an amenable number.

21026668 is a deficient number, since it is larger than the sum of its proper divisors (18769172).

21026668 is a wasteful number, since it uses less digits than its factorization.

21026668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1737 (or 1735 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 21026668 is about 4585.4844891243. The cubic root of 21026668 is about 276.0091539357.

The spelling of 21026668 in words is "twenty-one million, twenty-six thousand, six hundred sixty-eight".