21027487 has 16 divisors (see below), whose sum is σ = 24161760. Its totient is φ = 18235776.

The previous prime is 21027463. The next prime is 21027499. The reversal of 21027487 is 78472012.

It is not a de Polignac number, because 21027487 - 2¹¹ = 21025439 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21027287) 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 15 ways as a sum of consecutive naturals, for example, 37068 + ... + 37630.

It is an arithmetic number, because the mean of its divisors is an integer number (1510110).

Almost surely, 2^21027487 is an apocalyptic number.

21027487 is a deficient number, since it is larger than the sum of its proper divisors (3134273).

21027487 is an equidigital number, since it uses as much as digits as its factorization.

21027487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 619 (or 593 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 31.

The square root of 21027487 is about 4585.5737917953. The cubic root of 21027487 is about 276.0127374574.

Adding to 21027487 its reverse (78472012), we get a palindrome (99499499).

The spelling of 21027487 in words is "twenty-one million, twenty-seven thousand, four hundred eighty-seven".