21656035 has 4 divisors (see below), whose sum is σ = 25987248. Its totient is φ = 17324824.

The previous prime is 21656023. The next prime is 21656039. The reversal of 21656035 is 53065612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21656035 - 2¹¹ = 21653987 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21655994 and 21656012.

It is not an unprimeable number, because it can be changed into a prime (21656039) 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 3 ways as a sum of consecutive naturals, for example, 2165599 + ... + 2165608.

It is an arithmetic number, because the mean of its divisors is an integer number (6496812).

Almost surely, 2^21656035 is an apocalyptic number.

21656035 is a deficient number, since it is larger than the sum of its proper divisors (4331213).

21656035 is an equidigital number, since it uses as much as digits as its factorization.

21656035 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4331212.

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 21656035 is about 4653.6045169309. The cubic root of 21656035 is about 278.7359474640.

The spelling of 21656035 in words is "twenty-one million, six hundred fifty-six thousand, thirty-five".