21001441 has 4 divisors (see below), whose sum is σ = 22106800. Its totient is φ = 19896084.

The previous prime is 21001429. The next prime is 21001447. The reversal of 21001441 is 14410012.

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 21001441 - 2²³ = 12612833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001447) 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, 552651 + ... + 552688.

It is an arithmetic number, because the mean of its divisors is an integer number (5526700).

Almost surely, 2^21001441 is an apocalyptic number.

It is an amenable number.

21001441 is a deficient number, since it is larger than the sum of its proper divisors (1105359).

21001441 is a wasteful number, since it uses less digits than its factorization.

21001441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1105358.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 21001441 is about 4582.7329182487. The cubic root of 21001441 is about 275.8987279854.

Adding to 21001441 its reverse (14410012), we get a palindrome (35411453).

The spelling of 21001441 in words is "twenty-one million, one thousand, four hundred forty-one".