21856341 has 16 divisors (see below), whose sum is σ = 32115776. Its totient is φ = 13136256.

The previous prime is 21856337. The next prime is 21856349. The reversal of 21856341 is 14365812.

It is not a de Polignac number, because 21856341 - 2² = 21856337 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21856299 and 21856308.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21856349) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4840 + ... + 8193.

It is an arithmetic number, because the mean of its divisors is an integer number (2007236).

Almost surely, 2^21856341 is an apocalyptic number.

It is an amenable number.

21856341 is a deficient number, since it is larger than the sum of its proper divisors (10259435).

21856341 is a wasteful number, since it uses less digits than its factorization.

21856341 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13092.

The product of its digits is 5760, while the sum is 30.

The square root of 21856341 is about 4675.0765769129. The cubic root of 21856341 is about 279.5926943595.

The spelling of 21856341 in words is "twenty-one million, eight hundred fifty-six thousand, three hundred forty-one".