21778774 has 8 divisors (see below), whose sum is σ = 32704848. Its totient is φ = 10877160.

The previous prime is 21778763. The next prime is 21778777. The reversal of 21778774 is 47787712.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21778774.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21778777) 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 3 ways as a sum of consecutive naturals, for example, 3697 + ... + 7564.

It is an arithmetic number, because the mean of its divisors is an integer number (4088106).

Almost surely, 2^21778774 is an apocalyptic number.

21778774 is a deficient number, since it is larger than the sum of its proper divisors (10926074).

21778774 is a wasteful number, since it uses less digits than its factorization.

21778774 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12230.

The product of its digits is 153664, while the sum is 43.

The square root of 21778774 is about 4666.7734035413. The cubic root of 21778774 is about 279.2615490752.

The spelling of 21778774 in words is "twenty-one million, seven hundred seventy-eight thousand, seven hundred seventy-four".