21854071 has 4 divisors (see below), whose sum is σ = 22804272. Its totient is φ = 20903872.

The previous prime is 21854059. The next prime is 21854089. The reversal of 21854071 is 17045812.

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

It is not a de Polignac number, because 21854071 - 2¹⁷ = 21722999 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21854011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 475066 + ... + 475111.

It is an arithmetic number, because the mean of its divisors is an integer number (5701068).

Almost surely, 2^21854071 is an apocalyptic number.

21854071 is a deficient number, since it is larger than the sum of its proper divisors (950201).

21854071 is an equidigital number, since it uses as much as digits as its factorization.

21854071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 950200.

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 21854071 is about 4674.8337938370. The cubic root of 21854071 is about 279.5830145235.

Adding to 21854071 its reverse (17045812), we get a palindrome (38899883).

It can be divided in two parts, 218 and 54071, that added together give a square (54289 = 233²).

The spelling of 21854071 in words is "twenty-one million, eight hundred fifty-four thousand, seventy-one".