21316545 has 24 divisors (see below), whose sum is σ = 37093056. Its totient is φ = 11324448.

The previous prime is 21316531. The next prime is 21316553. The reversal of 21316545 is 54561312.

21316545 is a `hidden beast` number, since 2 + 1 + 3 + 1 + 654 + 5 = 666.

It is not a de Polignac number, because 21316545 - 2⁵ = 21316513 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13044 + ... + 14586.

It is an arithmetic number, because the mean of its divisors is an integer number (1545544).

Almost surely, 2^21316545 is an apocalyptic number.

It is an amenable number.

21316545 is a deficient number, since it is larger than the sum of its proper divisors (15776511).

21316545 is a wasteful number, since it uses less digits than its factorization.

21316545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1861 (or 1858 counting only the distinct ones).

The product of its digits is 3600, while the sum is 27.

The square root of 21316545 is about 4616.9844054318. The cubic root of 21316545 is about 277.2717382715.

Adding to 21316545 its reverse (54561312), we get a palindrome (75877857).

The spelling of 21316545 in words is "twenty-one million, three hundred sixteen thousand, five hundred forty-five".