21366441 has 12 divisors (see below), whose sum is σ = 31235568. Its totient is φ = 14072184.

The previous prime is 21366407. The next prime is 21366463. The reversal of 21366441 is 14466312.

21366441 is a `hidden beast` number, since 2 + 13 + 6 + 644 + 1 = 666.

It is not a de Polignac number, because 21366441 - 2⁶ = 21366377 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21366041) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13555 + ... + 15048.

It is an arithmetic number, because the mean of its divisors is an integer number (2602964).

Almost surely, 2^21366441 is an apocalyptic number.

It is an amenable number.

21366441 is a deficient number, since it is larger than the sum of its proper divisors (9869127).

21366441 is a wasteful number, since it uses less digits than its factorization.

21366441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28692 (or 28689 counting only the distinct ones).

The product of its digits is 3456, while the sum is 27.

The square root of 21366441 is about 4622.3847741182. The cubic root of 21366441 is about 277.4879079221.

The spelling of 21366441 in words is "twenty-one million, three hundred sixty-six thousand, four hundred forty-one".