21890768 has 10 divisors (see below), whose sum is σ = 42413394. Its totient is φ = 10945376.

The previous prime is 21890723. The next prime is 21890773. The reversal of 21890768 is 86709812.

It can be written as a sum of positive squares in only one way, i.e., 20866624 + 1024144 = 4568^2 + 1012^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 684071 + ... + 684102.

Almost surely, 2^21890768 is an apocalyptic number.

It is an amenable number.

21890768 is a deficient number, since it is larger than the sum of its proper divisors (20522626).

21890768 is a wasteful number, since it uses less digits than its factorization.

21890768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1368181 (or 1368175 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 41.

The square root of 21890768 is about 4678.7570999145. The cubic root of 21890768 is about 279.7394174275.

The spelling of 21890768 in words is "twenty-one million, eight hundred ninety thousand, seven hundred sixty-eight".