21280654 has 4 divisors (see below), whose sum is σ = 31920984. Its totient is φ = 10640326.

The previous prime is 21280639. The next prime is 21280687. The reversal of 21280654 is 45608212.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5320162 + ... + 5320165.

It is an arithmetic number, because the mean of its divisors is an integer number (7980246).

Almost surely, 2^21280654 is an apocalyptic number.

21280654 is a deficient number, since it is larger than the sum of its proper divisors (10640330).

21280654 is a wasteful number, since it uses less digits than its factorization.

21280654 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10640329.

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 21280654 is about 4613.0959235637. The cubic root of 21280654 is about 277.1160352657.

Adding to 21280654 its reverse (45608212), we get a palindrome (66888866).

The spelling of 21280654 in words is "twenty-one million, two hundred eighty thousand, six hundred fifty-four".