21725135 has 8 divisors (see below), whose sum is σ = 26108016. Its totient is φ = 17354880.

The previous prime is 21725111. The next prime is 21725149. The reversal of 21725135 is 53152712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21725135 - 2¹⁰ = 21724111 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1175 + ... + 6695.

It is an arithmetic number, because the mean of its divisors is an integer number (3263502).

Almost surely, 2^21725135 is an apocalyptic number.

21725135 is a deficient number, since it is larger than the sum of its proper divisors (4382881).

21725135 is an equidigital number, since it uses as much as digits as its factorization.

21725135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6313.

The product of its digits is 2100, while the sum is 26.

The square root of 21725135 is about 4661.0229563906. The cubic root of 21725135 is about 279.0320959294.

Adding to 21725135 its reverse (53152712), we get a palindrome (74877847).

It can be divided in two parts, 217 and 25135, that added together give a palindrome (25352).

The spelling of 21725135 in words is "twenty-one million, seven hundred twenty-five thousand, one hundred thirty-five".