21009076 has 24 divisors (see below), whose sum is σ = 42469056. Its totient is φ = 8987520.

The previous prime is 21009067. The next prime is 21009091. The reversal of 21009076 is 67090012.

It is a self number, because there is not a number n which added to its sum of digits gives 21009076.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13296 + ... + 14791.

It is an arithmetic number, because the mean of its divisors is an integer number (1769544).

Almost surely, 2^21009076 is an apocalyptic number.

It is an amenable number.

21009076 is an abundant number, since it is smaller than the sum of its proper divisors (21459980).

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

21009076 is a wasteful number, since it uses less digits than its factorization.

21009076 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28119 (or 28117 counting only the distinct ones).

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 21009076 is about 4583.5658607682. The cubic root of 21009076 is about 275.9321579387.

Adding to 21009076 its reverse (67090012), we get a palindrome (88099088).

The spelling of 21009076 in words is "twenty-one million, nine thousand, seventy-six".