21065487 has 8 divisors (see below), whose sum is σ = 28483200. Its totient is φ = 13845720.

The previous prime is 21065479. The next prime is 21065489. The reversal of 21065487 is 78456012.

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

It is not a de Polignac number, because 21065487 - 2³ = 21065479 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21065489) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49237 + ... + 49662.

It is an arithmetic number, because the mean of its divisors is an integer number (3560400).

Almost surely, 2^21065487 is an apocalyptic number.

21065487 is a deficient number, since it is larger than the sum of its proper divisors (7417713).

21065487 is an equidigital number, since it uses as much as digits as its factorization.

21065487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98973.

The product of its (nonzero) digits is 13440, while the sum is 33.

The square root of 21065487 is about 4589.7153506508. The cubic root of 21065487 is about 276.1789036480.

The spelling of 21065487 in words is "twenty-one million, sixty-five thousand, four hundred eighty-seven".