21000366 has 12 divisors (see below), whose sum is σ = 45500832. Its totient is φ = 7000116.

The previous prime is 21000337. The next prime is 21000367. The reversal of 21000366 is 66300012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 1166687 = 21000366 / (2 + 1 + 0 + 0 + 0 + 3 + 6 + 6).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000367) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 583326 + ... + 583361.

It is an arithmetic number, because the mean of its divisors is an integer number (3791736).

Almost surely, 2^21000366 is an apocalyptic number.

21000366 is an abundant number, since it is smaller than the sum of its proper divisors (24500466).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21000366 is a wasteful number, since it uses less digits than its factorization.

21000366 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1166695 (or 1166692 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 21000366 is about 4582.6156286558. The cubic root of 21000366 is about 275.8940204324.

Adding to 21000366 its reverse (66300012), we get a palindrome (87300378).

The spelling of 21000366 in words is "twenty-one million, three hundred sixty-six", and thus it is an aban number.