21487147 has 8 divisors (see below), whose sum is σ = 23488560. Its totient is φ = 19493760.

The previous prime is 21487117. The next prime is 21487153. The reversal of 21487147 is 74178412.

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

It is not a de Polignac number, because 21487147 - 2¹⁵ = 21454379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21487117) 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, 4543 + ... + 7975.

It is an arithmetic number, because the mean of its divisors is an integer number (2936070).

Almost surely, 2^21487147 is an apocalyptic number.

21487147 is a deficient number, since it is larger than the sum of its proper divisors (2001413).

21487147 is a wasteful number, since it uses less digits than its factorization.

21487147 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4013.

The product of its digits is 12544, while the sum is 34.

The square root of 21487147 is about 4635.4230659132. The cubic root of 21487147 is about 278.0094669240.

The spelling of 21487147 in words is "twenty-one million, four hundred eighty-seven thousand, one hundred forty-seven".