21788068 has 6 divisors (see below), whose sum is σ = 38129126. Its totient is φ = 10894032.

The previous prime is 21788029. The next prime is 21788083. The reversal of 21788068 is 86088712.

It can be written as a sum of positive squares in only one way, i.e., 21734244 + 53824 = 4662^2 + 232^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21788068.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2723505 + ... + 2723512.

Almost surely, 2^21788068 is an apocalyptic number.

It is an amenable number.

21788068 is a deficient number, since it is larger than the sum of its proper divisors (16341058).

21788068 is a wasteful number, since it uses less digits than its factorization.

21788068 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5447021 (or 5447019 counting only the distinct ones).

The product of its (nonzero) digits is 43008, while the sum is 40.

The square root of 21788068 is about 4667.7690602685. The cubic root of 21788068 is about 279.3012679887.

The spelling of 21788068 in words is "twenty-one million, seven hundred eighty-eight thousand, sixty-eight".