21145710 has 16 divisors (see below), whose sum is σ = 50749776. Its totient is φ = 5638848.

The previous prime is 21145699. The next prime is 21145741. The reversal of 21145710 is 1754112.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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, 352399 + ... + 352458.

It is an arithmetic number, because the mean of its divisors is an integer number (3171861).

Almost surely, 2^21145710 is an apocalyptic number.

21145710 is an abundant number, since it is smaller than the sum of its proper divisors (29604066).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21145710 is a wasteful number, since it uses less digits than its factorization.

21145710 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 704867.

The product of its (nonzero) digits is 280, while the sum is 21.

The square root of 21145710 is about 4598.4464768006. The cubic root of 21145710 is about 276.5290472161.

Adding to 21145710 its reverse (1754112), we get a palindrome (22899822).

The spelling of 21145710 in words is "twenty-one million, one hundred forty-five thousand, seven hundred ten".