21956837 has 8 divisors (see below), whose sum is σ = 26414400. Its totient is φ = 17829504.

The previous prime is 21956827. The next prime is 21956839. The reversal of 21956837 is 73865912.

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

It is not a de Polignac number, because 21956837 - 2¹⁸ = 21694693 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21956794 and 21956803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21956839) 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, 82412 + ... + 82677.

It is an arithmetic number, because the mean of its divisors is an integer number (3301800).

Almost surely, 2^21956837 is an apocalyptic number.

It is an amenable number.

21956837 is a deficient number, since it is larger than the sum of its proper divisors (4457563).

21956837 is a wasteful number, since it uses less digits than its factorization.

21956837 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165115.

The product of its digits is 90720, while the sum is 41.

The square root of 21956837 is about 4685.8123095148. The cubic root of 21956837 is about 280.0205639659.

The spelling of 21956837 in words is "twenty-one million, nine hundred fifty-six thousand, eight hundred thirty-seven".