21544641 has 6 divisors (see below), whose sum is σ = 31120050. Its totient is φ = 14363088.

The previous prime is 21544631. The next prime is 21544669. The reversal of 21544641 is 14644512.

21544641 is a `hidden beast` number, since 2 + 15 + 4 + 4 + 641 = 666.

It can be written as a sum of positive squares in only one way, i.e., 13727025 + 7817616 = 3705^2 + 2796^2 .

It is not a de Polignac number, because 21544641 - 2⁷ = 21544513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21544631) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1196916 + ... + 1196933.

It is an arithmetic number, because the mean of its divisors is an integer number (5186675).

Almost surely, 2^21544641 is an apocalyptic number.

It is an amenable number.

21544641 is a deficient number, since it is larger than the sum of its proper divisors (9575409).

21544641 is a wasteful number, since it uses less digits than its factorization.

21544641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2393855 (or 2393852 counting only the distinct ones).

The product of its digits is 3840, while the sum is 27.

The square root of 21544641 is about 4641.6205144324. The cubic root of 21544641 is about 278.2572063628.

The spelling of 21544641 in words is "twenty-one million, five hundred forty-four thousand, six hundred forty-one".