21641473 has 4 divisors (see below), whose sum is σ = 24733120. Its totient is φ = 18549828.

The previous prime is 21641467. The next prime is 21641483. The reversal of 21641473 is 37414612.

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 a de Polignac number, because none of the positive numbers 2^k-21641473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21641483) 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, 1545813 + ... + 1545826.

It is an arithmetic number, because the mean of its divisors is an integer number (6183280).

Almost surely, 2^21641473 is an apocalyptic number.

It is an amenable number.

21641473 is a deficient number, since it is larger than the sum of its proper divisors (3091647).

21641473 is an equidigital number, since it uses as much as digits as its factorization.

21641473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3091646.

The product of its digits is 4032, while the sum is 28.

The square root of 21641473 is about 4652.0396601921. The cubic root of 21641473 is about 278.6734573701.

The spelling of 21641473 in words is "twenty-one million, six hundred forty-one thousand, four hundred seventy-three".