21025711 has 4 divisors (see below), whose sum is σ = 24029392. Its totient is φ = 18022032.

The previous prime is 21025691. The next prime is 21025729. The reversal of 21025711 is 11752012.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21025711 - 2¹¹ = 21023663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21025751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1501830 + ... + 1501843.

It is an arithmetic number, because the mean of its divisors is an integer number (6007348).

Almost surely, 2^21025711 is an apocalyptic number.

21025711 is a deficient number, since it is larger than the sum of its proper divisors (3003681).

21025711 is an equidigital number, since it uses as much as digits as its factorization.

21025711 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3003680.

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 21025711 is about 4585.3801369134. The cubic root of 21025711 is about 276.0049664793.

Adding to 21025711 its reverse (11752012), we get a palindrome (32777723).

It can be divided in two parts, 21025 and 711, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 21025711 in words is "twenty-one million, twenty-five thousand, seven hundred eleven".