21779430 has 16 divisors (see below), whose sum is σ = 52270704. Its totient is φ = 5807840.

The previous prime is 21779423. The next prime is 21779447. The reversal of 21779430 is 3497712.

It is a super-2 number, since 2×21779430² = 948687142249800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21779391 and 21779400.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 362961 + ... + 363020.

It is an arithmetic number, because the mean of its divisors is an integer number (3266919).

Almost surely, 2^21779430 is an apocalyptic number.

21779430 is an abundant number, since it is smaller than the sum of its proper divisors (30491274).

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

21779430 is a wasteful number, since it uses less digits than its factorization.

21779430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 725991.

The product of its (nonzero) digits is 10584, while the sum is 33.

The square root of 21779430 is about 4666.8436871187. The cubic root of 21779430 is about 279.2643529327.

The spelling of 21779430 in words is "twenty-one million, seven hundred seventy-nine thousand, four hundred thirty".