21028611 has 12 divisors (see below), whose sum is σ = 29593032. Its totient is φ = 13280544.

The previous prime is 21028597. The next prime is 21028619. The reversal of 21028611 is 11682012.

It is not a de Polignac number, because 21028611 - 2¹⁴ = 21012227 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21028619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8626 + ... + 10791.

It is an arithmetic number, because the mean of its divisors is an integer number (2466086).

Almost surely, 2^21028611 is an apocalyptic number.

21028611 is a deficient number, since it is larger than the sum of its proper divisors (8564421).

21028611 is a wasteful number, since it uses less digits than its factorization.

21028611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19458 (or 19439 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 21028611 is about 4585.6963484295. The cubic root of 21028611 is about 276.0176553503.

The spelling of 21028611 in words is "twenty-one million, twenty-eight thousand, six hundred eleven".