21778698 has 8 divisors (see below), whose sum is σ = 43557408. Its totient is φ = 7259564.

The previous prime is 21778697. The next prime is 21778703. The reversal of 21778698 is 89687712.

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

21778698 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (21778697) 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, 1814886 + ... + 1814897.

It is an arithmetic number, because the mean of its divisors is an integer number (5444676).

Almost surely, 2^21778698 is an apocalyptic number.

21778698 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21778698 is a wasteful number, since it uses less digits than its factorization.

21778698 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3629788.

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

The square root of 21778698 is about 4666.7652608632. The cubic root of 21778698 is about 279.2612242344.

The spelling of 21778698 in words is "twenty-one million, seven hundred seventy-eight thousand, six hundred ninety-eight".