21140487 has 8 divisors (see below), whose sum is σ = 31319280. Its totient is φ = 14093640.

The previous prime is 21140423. The next prime is 21140501. The reversal of 21140487 is 78404112.

It is not a de Polignac number, because 21140487 - 2⁶ = 21140423 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 782981 = 21140487 / (2 + 1 + 1 + 4 + 0 + 4 + 8 + 7).

It is a self number, because there is not a number n which added to its sum of digits gives 21140487.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21141487) 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, 391464 + ... + 391517.

It is an arithmetic number, because the mean of its divisors is an integer number (3914910).

Almost surely, 2^21140487 is an apocalyptic number.

21140487 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21140487 is a deficient number, since it is larger than the sum of its proper divisors (10178793).

21140487 is an equidigital number, since it uses as much as digits as its factorization.

21140487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 782990 (or 782984 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 21140487 is about 4597.8785325408. The cubic root of 21140487 is about 276.5062777412.

Adding to 21140487 its reverse (78404112), we get a palindrome (99544599).

The spelling of 21140487 in words is "twenty-one million, one hundred forty thousand, four hundred eighty-seven".