21155933 has 8 divisors (see below), whose sum is σ = 21502368. Its totient is φ = 20812464.

The previous prime is 21155921. The next prime is 21155977. The reversal of 21155933 is 33955112.

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

It is a cyclic number.

It is not a de Polignac number, because 21155933 - 2⁴ = 21155917 is a prime.

It is a super-2 number, since 2×21155933² = 895147002200978, 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 = 21155896 and 21155905.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16835 + ... + 18047.

It is an arithmetic number, because the mean of its divisors is an integer number (2687796).

Almost surely, 2^21155933 is an apocalyptic number.

It is an amenable number.

21155933 is a deficient number, since it is larger than the sum of its proper divisors (346435).

21155933 is a wasteful number, since it uses less digits than its factorization.

21155933 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1483.

The product of its digits is 4050, while the sum is 29.

The square root of 21155933 is about 4599.5579135391. The cubic root of 21155933 is about 276.5736031569.

The spelling of 21155933 in words is "twenty-one million, one hundred fifty-five thousand, nine hundred thirty-three".