21240654 has 8 divisors (see below), whose sum is σ = 42481320. Its totient is φ = 7080216.

The previous prime is 21240643. The next prime is 21240683. The reversal of 21240654 is 45604212.

It is a sphenic number, since it is the product of 3 distinct primes.

21240654 is an admirable number.

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 3 ways as a sum of consecutive naturals, for example, 1770049 + ... + 1770060.

It is an arithmetic number, because the mean of its divisors is an integer number (5310165).

Almost surely, 2^21240654 is an apocalyptic number.

21240654 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21240654 is a wasteful number, since it uses less digits than its factorization.

21240654 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3540114.

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 21240654 is about 4608.7584011315. The cubic root of 21240654 is about 276.9423001019.

Adding to 21240654 its reverse (45604212), we get a palindrome (66844866).

The spelling of 21240654 in words is "twenty-one million, two hundred forty thousand, six hundred fifty-four".