21105316 has 6 divisors (see below), whose sum is σ = 36934310. Its totient is φ = 10552656.

The previous prime is 21105307. The next prime is 21105341. The reversal of 21105316 is 61350112.

It can be written as a sum of positive squares in only one way, i.e., 12960000 + 8145316 = 3600^2 + 2854^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21105293 and 21105302.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2638161 + ... + 2638168.

Almost surely, 2^21105316 is an apocalyptic number.

It is an amenable number.

21105316 is a deficient number, since it is larger than the sum of its proper divisors (15828994).

21105316 is a wasteful number, since it uses less digits than its factorization.

21105316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5276333 (or 5276331 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 21105316 is about 4594.0522417578. The cubic root of 21105316 is about 276.3528533289.

Adding to 21105316 its reverse (61350112), we get a palindrome (82455428).

The spelling of 21105316 in words is "twenty-one million, one hundred five thousand, three hundred sixteen".