21774379 has 4 divisors (see below), whose sum is σ = 23753880. Its totient is φ = 19794880.

The previous prime is 21774359. The next prime is 21774391. The reversal of 21774379 is 97347712.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21774379 - 2⁷ = 21774251 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21774329) 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, 989734 + ... + 989755.

It is an arithmetic number, because the mean of its divisors is an integer number (5938470).

Almost surely, 2^21774379 is an apocalyptic number.

21774379 is a deficient number, since it is larger than the sum of its proper divisors (1979501).

21774379 is a wasteful number, since it uses less digits than its factorization.

21774379 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1979500.

The product of its digits is 74088, while the sum is 40.

The square root of 21774379 is about 4666.3024976956. The cubic root of 21774379 is about 279.2427626323.

It can be divided in two parts, 2177 and 4379, that added together give a palindrome (6556).

The spelling of 21774379 in words is "twenty-one million, seven hundred seventy-four thousand, three hundred seventy-nine".