21987010 has 8 divisors (see below), whose sum is σ = 39576636. Its totient is φ = 8794800.

The previous prime is 21986989. The next prime is 21987019. The reversal of 21987010 is 1078912.

It can be written as a sum of positive squares in 2 ways, for example, as 21986721 + 289 = 4689^2 + 17^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 21987010.

It is not an unprimeable number, because it can be changed into a prime (21987019) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1099341 + ... + 1099360.

Almost surely, 2^21987010 is an apocalyptic number.

21987010 is a deficient number, since it is larger than the sum of its proper divisors (17589626).

21987010 is a wasteful number, since it uses less digits than its factorization.

21987010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2198708.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 21987010 is about 4689.0308167040. The cubic root of 21987010 is about 280.1487729790.

The spelling of 21987010 in words is "twenty-one million, nine hundred eighty-seven thousand, ten".