21365416 has 8 divisors (see below), whose sum is σ = 40060170. Its totient is φ = 10682704.

The previous prime is 21365411. The next prime is 21365419. The reversal of 21365416 is 61456312.

It can be written as a sum of positive squares in only one way, i.e., 14364100 + 7001316 = 3790^2 + 2646^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21365411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1335331 + ... + 1335346.

Almost surely, 2^21365416 is an apocalyptic number.

It is an amenable number.

21365416 is a deficient number, since it is larger than the sum of its proper divisors (18694754).

21365416 is a wasteful number, since it uses less digits than its factorization.

21365416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2670683 (or 2670679 counting only the distinct ones).

The product of its digits is 4320, while the sum is 28.

The square root of 21365416 is about 4622.2738992838. The cubic root of 21365416 is about 277.4834705951.

The spelling of 21365416 in words is "twenty-one million, three hundred sixty-five thousand, four hundred sixteen".