21125641 has 8 divisors (see below), whose sum is σ = 21643200. Its totient is φ = 20612592.

The previous prime is 21125639. The next prime is 21125647. The reversal of 21125641 is 14652112.

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

It is a cyclic number.

It is not a de Polignac number, because 21125641 - 2¹ = 21125639 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21125647) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9546 + ... + 11548.

It is an arithmetic number, because the mean of its divisors is an integer number (2705400).

Almost surely, 2^21125641 is an apocalyptic number.

It is an amenable number.

21125641 is a deficient number, since it is larger than the sum of its proper divisors (517559).

21125641 is a wasteful number, since it uses less digits than its factorization.

21125641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2255.

The product of its digits is 480, while the sum is 22.

The square root of 21125641 is about 4596.2638087908. The cubic root of 21125641 is about 276.4415366672.

Adding to 21125641 its reverse (14652112), we get a palindrome (35777753).

It can be divided in two parts, 211 and 25641, that added together give a palindrome (25852).

The spelling of 21125641 in words is "twenty-one million, one hundred twenty-five thousand, six hundred forty-one".