21575021 has 8 divisors (see below), whose sum is σ = 23729664. Its totient is φ = 19491120.

The previous prime is 21575017. The next prime is 21575041. The reversal of 21575021 is 12057512.

It is a happy number.

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 21575021 - 2² = 21575017 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21575011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17045 + ... + 18266.

It is an arithmetic number, because the mean of its divisors is an integer number (2966208).

Almost surely, 2^21575021 is an apocalyptic number.

It is an amenable number.

21575021 is a deficient number, since it is larger than the sum of its proper divisors (2154643).

21575021 is a wasteful number, since it uses less digits than its factorization.

21575021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35371.

The product of its (nonzero) digits is 700, while the sum is 23.

The square root of 21575021 is about 4644.8919255457. The cubic root of 21575021 is about 278.3879346747.

The spelling of 21575021 in words is "twenty-one million, five hundred seventy-five thousand, twenty-one".