21000641 has 8 divisors (see below), whose sum is σ = 21609984. Its totient is φ = 20396880.

The previous prime is 21000613. The next prime is 21000673. The reversal of 21000641 is 14600012.

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 21000641 - 2²² = 16806337 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21000601) 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, 6935 + ... + 9491.

It is an arithmetic number, because the mean of its divisors is an integer number (2701248).

Almost surely, 2^21000641 is an apocalyptic number.

It is an amenable number.

21000641 is a deficient number, since it is larger than the sum of its proper divisors (609343).

21000641 is a wasteful number, since it uses less digits than its factorization.

21000641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2791.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 21000641 is about 4582.6456332560. The cubic root of 21000641 is about 275.8952247054.

Adding to 21000641 its reverse (14600012), we get a palindrome (35600653).

The spelling of 21000641 in words is "twenty-one million, six hundred forty-one", and thus it is an aban number.