21987310 has 16 divisors (see below), whose sum is σ = 41298336. Its totient is φ = 8412448.

The previous prime is 21987299. The next prime is 21987331. The reversal of 21987310 is 1378912.

It is a super-2 number, since 2×21987310² = 966883602072200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47569 + ... + 48028.

It is an arithmetic number, because the mean of its divisors is an integer number (2581146).

Almost surely, 2^21987310 is an apocalyptic number.

21987310 is a deficient number, since it is larger than the sum of its proper divisors (19311026).

21987310 is a wasteful number, since it uses less digits than its factorization.

21987310 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95627.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 21987310 is about 4689.0628061479. The cubic root of 21987310 is about 280.1500471290.

The spelling of 21987310 in words is "twenty-one million, nine hundred eighty-seven thousand, three hundred ten".