21956091 has 8 divisors (see below), whose sum is σ = 30219264. Its totient is φ = 14165160.

The previous prime is 21956089. The next prime is 21956093. The reversal of 21956091 is 19065912.

It is an interprime number because it is at equal distance from previous prime (21956089) and next prime (21956093).

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

It is not a de Polignac number, because 21956091 - 2¹ = 21956089 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21956093) 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, 117951 + ... + 118136.

It is an arithmetic number, because the mean of its divisors is an integer number (3777408).

Almost surely, 2^21956091 is an apocalyptic number.

21956091 is a deficient number, since it is larger than the sum of its proper divisors (8263173).

21956091 is a wasteful number, since it uses less digits than its factorization.

21956091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 236121.

The product of its (nonzero) digits is 4860, while the sum is 33.

The square root of 21956091 is about 4685.7327068453. The cubic root of 21956091 is about 280.0173926271.

The spelling of 21956091 in words is "twenty-one million, nine hundred fifty-six thousand, ninety-one".