21953211 has 8 divisors (see below), whose sum is σ = 33452544. Its totient is φ = 12544680.

The previous prime is 21953167. The next prime is 21953221. The reversal of 21953211 is 11235912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21953211 - 2¹⁵ = 21920443 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21953221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 522675 + ... + 522716.

It is an arithmetic number, because the mean of its divisors is an integer number (4181568).

Almost surely, 2^21953211 is an apocalyptic number.

21953211 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21953211 is a deficient number, since it is larger than the sum of its proper divisors (11499333).

21953211 is a wasteful number, since it uses less digits than its factorization.

21953211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1045401.

The product of its digits is 540, while the sum is 24.

The square root of 21953211 is about 4685.4253809019. The cubic root of 21953211 is about 280.0051487148.

The spelling of 21953211 in words is "twenty-one million, nine hundred fifty-three thousand, two hundred eleven".