21704841 has 10 divisors (see below), whose sum is σ = 32423402. Its totient is φ = 14469840.

The previous prime is 21704833. The next prime is 21704857. The reversal of 21704841 is 14840712.

It can be written as a sum of positive squares in only one way, i.e., 16842816 + 4862025 = 4104^2 + 2205^2 .

It is not a de Polignac number, because 21704841 - 2³ = 21704833 is a prime.

It is a super-2 number, since 2×21704841² = 942200245670562, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21704831) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 133900 + ... + 134061.

Almost surely, 2^21704841 is an apocalyptic number.

It is an amenable number.

21704841 is a deficient number, since it is larger than the sum of its proper divisors (10718561).

21704841 is an equidigital number, since it uses as much as digits as its factorization.

21704841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267973 (or 267964 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 21704841 is about 4658.8454578361. The cubic root of 21704841 is about 278.9451852077.

The spelling of 21704841 in words is "twenty-one million, seven hundred four thousand, eight hundred forty-one".