21259678 has 16 divisors (see below), whose sum is σ = 35446896. Its totient is φ = 9480640.

The previous prime is 21259669. The next prime is 21259681. The reversal of 21259678 is 87695212.

It is a self number, because there is not a number n which added to its sum of digits gives 21259678.

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, 7951 + ... + 10282.

It is an arithmetic number, because the mean of its divisors is an integer number (2215431).

Almost surely, 2^21259678 is an apocalyptic number.

21259678 is a deficient number, since it is larger than the sum of its proper divisors (14187218).

21259678 is a wasteful number, since it uses less digits than its factorization.

21259678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18299.

The product of its digits is 60480, while the sum is 40.

The square root of 21259678 is about 4610.8218356384. The cubic root of 21259678 is about 277.0249557206.

The spelling of 21259678 in words is "twenty-one million, two hundred fifty-nine thousand, six hundred seventy-eight".