21921011 has 8 divisors (see below), whose sum is σ = 25110624. Its totient is φ = 18745920.

The previous prime is 21920989. The next prime is 21921017. The reversal of 21921011 is 11012912.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21921011 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21921017) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 170 + ... + 6623.

It is an arithmetic number, because the mean of its divisors is an integer number (3138828).

Almost surely, 2^21921011 is an apocalyptic number.

21921011 is a deficient number, since it is larger than the sum of its proper divisors (3189613).

21921011 is an equidigital number, since it uses as much as digits as its factorization.

21921011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7261.

The product of its (nonzero) digits is 36, while the sum is 17.

The square root of 21921011 is about 4681.9879324919. The cubic root of 21921011 is about 279.8681820003.

Adding to 21921011 its reverse (11012912), we get a palindrome (32933923).

The spelling of 21921011 in words is "twenty-one million, nine hundred twenty-one thousand, eleven".