21516344 has 8 divisors (see below), whose sum is σ = 40343160. Its totient is φ = 10758168.

The previous prime is 21516311. The next prime is 21516359. The reversal of 21516344 is 44361512.

It is a tau number, because it is divible by the number of its divisors (8).

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, 1344764 + ... + 1344779.

It is an arithmetic number, because the mean of its divisors is an integer number (5042895).

Almost surely, 2^21516344 is an apocalyptic number.

It is an amenable number.

21516344 is a deficient number, since it is larger than the sum of its proper divisors (18826816).

21516344 is a wasteful number, since it uses less digits than its factorization.

21516344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2689549 (or 2689545 counting only the distinct ones).

The product of its digits is 2880, while the sum is 26.

The square root of 21516344 is about 4638.5713317788. The cubic root of 21516344 is about 278.1353308287.

Adding to 21516344 its reverse (44361512), we get a palindrome (65877856).

The spelling of 21516344 in words is "twenty-one million, five hundred sixteen thousand, three hundred forty-four".