21311716 has 6 divisors (see below), whose sum is σ = 37295510. Its totient is φ = 10655856.

The previous prime is 21311701. The next prime is 21311729. The reversal of 21311716 is 61711312.

It can be written as a sum of positive squares in only one way, i.e., 18455616 + 2856100 = 4296^2 + 1690^2 .

It is a super-3 number, since 3×21311716³ (a number of 23 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2663961 + ... + 2663968.

Almost surely, 2^21311716 is an apocalyptic number.

It is an amenable number.

21311716 is a deficient number, since it is larger than the sum of its proper divisors (15983794).

21311716 is a wasteful number, since it uses less digits than its factorization.

21311716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5327933 (or 5327931 counting only the distinct ones).

The product of its digits is 252, while the sum is 22.

The square root of 21311716 is about 4616.4614154133. The cubic root of 21311716 is about 277.2507991943.

The spelling of 21311716 in words is "twenty-one million, three hundred eleven thousand, seven hundred sixteen".