21501316 has 12 divisors (see below), whose sum is σ = 38081232. Its totient is φ = 10620968.

The previous prime is 21501299. The next prime is 21501323. The reversal of 21501316 is 61310512.

It is a junction number, because it is equal to n+sod(n) for n = 21501293 and 21501302.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32050 + ... + 32713.

It is an arithmetic number, because the mean of its divisors is an integer number (3173436).

Almost surely, 2^21501316 is an apocalyptic number.

It is an amenable number.

21501316 is a deficient number, since it is larger than the sum of its proper divisors (16579916).

21501316 is a wasteful number, since it uses less digits than its factorization.

21501316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64850 (or 64848 counting only the distinct ones).

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

The square root of 21501316 is about 4636.9511535059. The cubic root of 21501316 is about 278.0705615962.

Adding to 21501316 its reverse (61310512), we get a palindrome (82811828).

The spelling of 21501316 in words is "twenty-one million, five hundred one thousand, three hundred sixteen".