18779561 has 4 divisors (see below), whose sum is σ = 18806400. Its totient is φ = 18752724.

The previous prime is 18779539. The next prime is 18779573. The reversal of 18779561 is 16597781.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18779561 - 2¹⁴ = 18763177 is a prime.

It is a super-2 number, since 2×18779561² = 705343822705442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18779531) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 12341 + ... + 13778.

It is an arithmetic number, because the mean of its divisors is an integer number (4701600).

Almost surely, 2^18779561 is an apocalyptic number.

It is an amenable number.

18779561 is a deficient number, since it is larger than the sum of its proper divisors (26839).

18779561 is an equidigital number, since it uses as much as digits as its factorization.

18779561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26838.

The product of its digits is 105840, while the sum is 44.

The square root of 18779561 is about 4333.5390848589. The cubic root of 18779561 is about 265.8041834327.

The spelling of 18779561 in words is "eighteen million, seven hundred seventy-nine thousand, five hundred sixty-one".