21057441 has 8 divisors (see below), whose sum is σ = 29728224. Its totient is φ = 13212480.

The previous prime is 21057433. The next prime is 21057467. The reversal of 21057441 is 14475012.

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

It is not a de Polignac number, because 21057441 - 2³ = 21057433 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21057431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 206395 + ... + 206496.

It is an arithmetic number, because the mean of its divisors is an integer number (3716028).

Almost surely, 2^21057441 is an apocalyptic number.

It is an amenable number.

21057441 is a deficient number, since it is larger than the sum of its proper divisors (8670783).

21057441 is a wasteful number, since it uses less digits than its factorization.

21057441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 412911.

The product of its (nonzero) digits is 1120, while the sum is 24.

The square root of 21057441 is about 4588.8387419913. The cubic root of 21057441 is about 276.1437368302.

The spelling of 21057441 in words is "twenty-one million, fifty-seven thousand, four hundred forty-one".