21798678 has 32 divisors (see below), whose sum is σ = 48673152. Its totient is φ = 6451200.

The previous prime is 21798653. The next prime is 21798683. The reversal of 21798678 is 87689712.

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 in 15 ways as a sum of consecutive naturals, for example, 1003 + ... + 6678.

It is an arithmetic number, because the mean of its divisors is an integer number (1521036).

Almost surely, 2^21798678 is an apocalyptic number.

21798678 is an abundant number, since it is smaller than the sum of its proper divisors (26874474).

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

21798678 is a wasteful number, since it uses less digits than its factorization.

21798678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7740.

The product of its digits is 338688, while the sum is 48.

The square root of 21798678 is about 4668.9054391795. The cubic root of 21798678 is about 279.3465971656.

The spelling of 21798678 in words is "twenty-one million, seven hundred ninety-eight thousand, six hundred seventy-eight".