21858678 has 12 divisors (see below), whose sum is σ = 47360508. Its totient is φ = 7286220.

The previous prime is 21858673. The next prime is 21858691. The reversal of 21858678 is 87685812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21858673) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 607168 + ... + 607203.

It is an arithmetic number, because the mean of its divisors is an integer number (3946709).

Almost surely, 2^21858678 is an apocalyptic number.

21858678 is an abundant number, since it is smaller than the sum of its proper divisors (25501830).

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

21858678 is a wasteful number, since it uses less digits than its factorization.

21858678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1214379 (or 1214376 counting only the distinct ones).

The product of its digits is 215040, while the sum is 45.

The square root of 21858678 is about 4675.3265126620. The cubic root of 21858678 is about 279.6026591997.

The spelling of 21858678 in words is "twenty-one million, eight hundred fifty-eight thousand, six hundred seventy-eight".