21120641 has 4 divisors (see below), whose sum is σ = 21801984. Its totient is φ = 20439300.

The previous prime is 21120637. The next prime is 21120661. The reversal of 21120641 is 14602112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21120641 - 2² = 21120637 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21120661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 340625 + ... + 340686.

It is an arithmetic number, because the mean of its divisors is an integer number (5450496).

Almost surely, 2^21120641 is an apocalyptic number.

It is an amenable number.

21120641 is a deficient number, since it is larger than the sum of its proper divisors (681343).

21120641 is an equidigital number, since it uses as much as digits as its factorization.

21120641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 681342.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 21120641 is about 4595.7198565622. The cubic root of 21120641 is about 276.4197256250.

Adding to 21120641 its reverse (14602112), we get a palindrome (35722753).

The spelling of 21120641 in words is "twenty-one million, one hundred twenty thousand, six hundred forty-one".