21778796 has 24 divisors (see below), whose sum is σ = 41176464. Its totient is φ = 10019520.

The previous prime is 21778793. The next prime is 21778811. The reversal of 21778796 is 69787712.

It is a self number, because there is not a number n which added to its sum of digits gives 21778796.

It is not an unprimeable number, because it can be changed into a prime (21778793) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25106 + ... + 25958.

It is an arithmetic number, because the mean of its divisors is an integer number (1715686).

Almost surely, 2^21778796 is an apocalyptic number.

21778796 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21778796 is a deficient number, since it is larger than the sum of its proper divisors (19397668).

21778796 is a wasteful number, since it uses less digits than its factorization.

21778796 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1361 (or 1359 counting only the distinct ones).

The product of its digits is 296352, while the sum is 47.

The square root of 21778796 is about 4666.7757606296. The cubic root of 21778796 is about 279.2616431079.

The spelling of 21778796 in words is "twenty-one million, seven hundred seventy-eight thousand, seven hundred ninety-six".