21145312 has 12 divisors (see below), whose sum is σ = 41629896. Its totient is φ = 10572640.

The previous prime is 21145307. The next prime is 21145343. The reversal of 21145312 is 21354112.

It is a self number, because there is not a number n which added to its sum of digits gives 21145312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330364 + ... + 330427.

It is an arithmetic number, because the mean of its divisors is an integer number (3469158).

Almost surely, 2^21145312 is an apocalyptic number.

It is an amenable number.

21145312 is a deficient number, since it is larger than the sum of its proper divisors (20484584).

21145312 is an equidigital number, since it uses as much as digits as its factorization.

21145312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 660801 (or 660793 counting only the distinct ones).

The product of its digits is 240, while the sum is 19.

The square root of 21145312 is about 4598.4032011123. The cubic root of 21145312 is about 276.5273122819.

Adding to 21145312 its reverse (21354112), we get a palindrome (42499424).

The spelling of 21145312 in words is "twenty-one million, one hundred forty-five thousand, three hundred twelve".