21854747 has 4 divisors (see below), whose sum is σ = 21958536. Its totient is φ = 21750960.

The previous prime is 21854743. The next prime is 21854771. The reversal of 21854747 is 74745812.

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 21854747 - 2² = 21854743 is a prime.

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

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21854747.

It is not an unprimeable number, because it can be changed into a prime (21854743) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51578 + ... + 51999.

It is an arithmetic number, because the mean of its divisors is an integer number (5489634).

Almost surely, 2^21854747 is an apocalyptic number.

21854747 is a deficient number, since it is larger than the sum of its proper divisors (103789).

21854747 is a wasteful number, since it uses less digits than its factorization.

21854747 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103788.

The product of its digits is 62720, while the sum is 38.

The square root of 21854747 is about 4674.9060953136. The cubic root of 21854747 is about 279.5858972231.

The spelling of 21854747 in words is "twenty-one million, eight hundred fifty-four thousand, seven hundred forty-seven".