21000774 has 16 divisors (see below), whose sum is σ = 43026480. Its totient is φ = 6829440.

The previous prime is 21000761. The next prime is 21000779. The reversal of 21000774 is 47700012.

It is a self number, because there is not a number n which added to its sum of digits gives 21000774.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000779) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42439 + ... + 42930.

It is an arithmetic number, because the mean of its divisors is an integer number (2689155).

Almost surely, 2^21000774 is an apocalyptic number.

21000774 is an abundant number, since it is smaller than the sum of its proper divisors (22025706).

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

21000774 is a wasteful number, since it uses less digits than its factorization.

21000774 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85415.

The product of its (nonzero) digits is 392, while the sum is 21.

The square root of 21000774 is about 4582.6601445012. The cubic root of 21000774 is about 275.8958071319.

Adding to 21000774 its reverse (47700012), we get a palindrome (68700786).

The spelling of 21000774 in words is "twenty-one million, seven hundred seventy-four", and thus it is an aban number.