21544851 has 8 divisors (see below), whose sum is σ = 28903360. Its totient is φ = 14274792.

The previous prime is 21544843. The next prime is 21544867. The reversal of 21544851 is 15844512.

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

It is not a de Polignac number, because 21544851 - 2³ = 21544843 is a prime.

It is a super-2 number, since 2×21544851² = 928361209224402, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21544451) 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, 21541 + ... + 22518.

It is an arithmetic number, because the mean of its divisors is an integer number (3612920).

Almost surely, 2^21544851 is an apocalyptic number.

21544851 is a deficient number, since it is larger than the sum of its proper divisors (7358509).

21544851 is a wasteful number, since it uses less digits than its factorization.

21544851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44225.

The product of its digits is 6400, while the sum is 30.

The square root of 21544851 is about 4641.6431357872. The cubic root of 21544851 is about 278.2581104364.

The spelling of 21544851 in words is "twenty-one million, five hundred forty-four thousand, eight hundred fifty-one".