21065288 has 8 divisors (see below), whose sum is σ = 39497430. Its totient is φ = 10532640.

The previous prime is 21065287. The next prime is 21065333. The reversal of 21065288 is 88256012.

It can be written as a sum of positive squares in only one way, i.e., 17960644 + 3104644 = 4238^2 + 1762^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (21065287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1316573 + ... + 1316588.

Almost surely, 2^21065288 is an apocalyptic number.

It is an amenable number.

21065288 is a deficient number, since it is larger than the sum of its proper divisors (18432142).

21065288 is a wasteful number, since it uses less digits than its factorization.

21065288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2633167 (or 2633163 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 21065288 is about 4589.6936716953. The cubic root of 21065288 is about 276.1780339827.

The spelling of 21065288 in words is "twenty-one million, sixty-five thousand, two hundred eighty-eight".