21911331 has 8 divisors (see below), whose sum is σ = 31462480. Its totient is φ = 13483872.

The previous prime is 21911321. The next prime is 21911333. The reversal of 21911331 is 13311912.

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

It is not a de Polignac number, because 21911331 - 2¹⁰ = 21910307 is a prime.

It is a super-2 number, since 2×21911331² = 960212852383122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21911298 and 21911307.

It is not an unprimeable number, because it can be changed into a prime (21911333) 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, 280876 + ... + 280953.

It is an arithmetic number, because the mean of its divisors is an integer number (3932810).

Almost surely, 2^21911331 is an apocalyptic number.

21911331 is a deficient number, since it is larger than the sum of its proper divisors (9551149).

21911331 is a wasteful number, since it uses less digits than its factorization.

21911331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 561845.

The product of its digits is 162, while the sum is 21.

The square root of 21911331 is about 4680.9540694179. The cubic root of 21911331 is about 279.8269806939.

The spelling of 21911331 in words is "twenty-one million, nine hundred eleven thousand, three hundred thirty-one".