21107487 has 8 divisors (see below), whose sum is σ = 28175536. Its totient is φ = 14055552.

The previous prime is 21107483. The next prime is 21107509. The reversal of 21107487 is 78470112.

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

It is not a de Polignac number, because 21107487 - 2² = 21107483 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 (21107483) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 538 + ... + 6519.

It is an arithmetic number, because the mean of its divisors is an integer number (3521942).

Almost surely, 2^21107487 is an apocalyptic number.

21107487 is a deficient number, since it is larger than the sum of its proper divisors (7068049).

21107487 is an equidigital number, since it uses as much as digits as its factorization.

21107487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8057.

The product of its (nonzero) digits is 3136, while the sum is 30.

The square root of 21107487 is about 4594.2885194554. The cubic root of 21107487 is about 276.3623286900.

Adding to 21107487 its reverse (78470112), we get a palindrome (99577599).

The spelling of 21107487 in words is "twenty-one million, one hundred seven thousand, four hundred eighty-seven".