21026788 has 6 divisors (see below), whose sum is σ = 36796886. Its totient is φ = 10513392.

The previous prime is 21026779. The next prime is 21026801. The reversal of 21026788 is 88762012.

It can be written as a sum of positive squares in only one way, i.e., 19289664 + 1737124 = 4392^2 + 1318^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2628345 + ... + 2628352.

Almost surely, 2^21026788 is an apocalyptic number.

It is an amenable number.

21026788 is a deficient number, since it is larger than the sum of its proper divisors (15770098).

21026788 is a wasteful number, since it uses less digits than its factorization.

21026788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5256701 (or 5256699 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 21026788 is about 4585.4975738735. The cubic root of 21026788 is about 276.0096789996.

The spelling of 21026788 in words is "twenty-one million, twenty-six thousand, seven hundred eighty-eight".