21520316 has 6 divisors (see below), whose sum is σ = 37660560. Its totient is φ = 10760156.

The previous prime is 21520307. The next prime is 21520361. The reversal of 21520316 is 61302512.

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, 2690036 + ... + 2690043.

It is an arithmetic number, because the mean of its divisors is an integer number (6276760).

Almost surely, 2^21520316 is an apocalyptic number.

It is an amenable number.

21520316 is a deficient number, since it is larger than the sum of its proper divisors (16140244).

21520316 is a wasteful number, since it uses less digits than its factorization.

21520316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5380083 (or 5380081 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 21520316 is about 4638.9994610907. Note that the first 3 decimals coincide. The cubic root of 21520316 is about 278.1524447268.

Adding to 21520316 its reverse (61302512), we get a palindrome (82822828).

The spelling of 21520316 in words is "twenty-one million, five hundred twenty thousand, three hundred sixteen".