21695641 has 8 divisors (see below), whose sum is σ = 23890464. Its totient is φ = 19537920.

The previous prime is 21695627. The next prime is 21695669. The reversal of 21695641 is 14659612.

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 21695641 - 2⁹ = 21695129 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21695597 and 21695606.

It is not an unprimeable number, because it can be changed into a prime (21695941) 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, 8040 + ... + 10393.

It is an arithmetic number, because the mean of its divisors is an integer number (2986308).

Almost surely, 2^21695641 is an apocalyptic number.

It is an amenable number.

21695641 is a deficient number, since it is larger than the sum of its proper divisors (2194823).

21695641 is a wasteful number, since it uses less digits than its factorization.

21695641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18551.

The product of its digits is 12960, while the sum is 34.

The square root of 21695641 is about 4657.8579840953. The cubic root of 21695641 is about 278.9057676053.

The spelling of 21695641 in words is "twenty-one million, six hundred ninety-five thousand, six hundred forty-one".