21000654 has 16 divisors (see below), whose sum is σ = 46668240. Its totient is φ = 7000200.

The previous prime is 21000613. The next prime is 21000673. The reversal of 21000654 is 45600012.

It is a happy number.

21000654 is a `hidden beast` number, since 2 + 10 + 0 + 0 + 654 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 194397 + ... + 194504.

It is an arithmetic number, because the mean of its divisors is an integer number (2916765).

Almost surely, 2^21000654 is an apocalyptic number.

21000654 is an abundant number, since it is smaller than the sum of its proper divisors (25667586).

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

21000654 is a wasteful number, since it uses less digits than its factorization.

21000654 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 388912 (or 388906 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21000654 is about 4582.6470516504. The cubic root of 21000654 is about 275.8952816344.

Adding to 21000654 its reverse (45600012), we get a palindrome (66600666).

The spelling of 21000654 in words is "twenty-one million, six hundred fifty-four", and thus it is an aban number.