21331678 has 8 divisors (see below), whose sum is σ = 32149800. Its totient is φ = 10615080.

The previous prime is 21331669. The next prime is 21331679. The reversal of 21331678 is 87613312.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21331679) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24853 + ... + 25696.

It is an arithmetic number, because the mean of its divisors is an integer number (4018725).

Almost surely, 2^21331678 is an apocalyptic number.

21331678 is a deficient number, since it is larger than the sum of its proper divisors (10818122).

21331678 is a wasteful number, since it uses less digits than its factorization.

21331678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50762.

The product of its digits is 6048, while the sum is 31.

The square root of 21331678 is about 4618.6229549510. The cubic root of 21331678 is about 277.3373361545.

The spelling of 21331678 in words is "twenty-one million, three hundred thirty-one thousand, six hundred seventy-eight".