21475211 has 4 divisors (see below), whose sum is σ = 21508752. Its totient is φ = 21441672.

The previous prime is 21475183. The next prime is 21475217. The reversal of 21475211 is 11257412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21475211 - 2⁶ = 21475147 is a prime.

It is a super-2 number, since 2×21475211² = 922369374989042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21475217) 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, 15791 + ... + 17096.

It is an arithmetic number, because the mean of its divisors is an integer number (5377188).

Almost surely, 2^21475211 is an apocalyptic number.

21475211 is a deficient number, since it is larger than the sum of its proper divisors (33541).

21475211 is an equidigital number, since it uses as much as digits as its factorization.

21475211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33540.

The product of its digits is 560, while the sum is 23.

The square root of 21475211 is about 4634.1354101925. The cubic root of 21475211 is about 277.9579797780.

The spelling of 21475211 in words is "twenty-one million, four hundred seventy-five thousand, two hundred eleven".