18779881 has 2 divisors, whose sum is σ = 18779882. Its totient is φ = 18779880.

The previous prime is 18779867. The next prime is 18779897. The reversal of 18779881 is 18897781.

18779881 is nontrivially palindromic in base 11.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11162281 + 7617600 = 3341^2 + 2760^2 .

It is a cyclic number.

It is not a de Polignac number, because 18779881 - 2¹⁹ = 18255593 is a prime.

It is a super-2 number, since 2×18779881² = 705367860748322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18779821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9389940 + 9389941.

It is an arithmetic number, because the mean of its divisors is an integer number (9389941).

Almost surely, 2^18779881 is an apocalyptic number.

It is an amenable number.

18779881 is a deficient number, since it is larger than the sum of its proper divisors (1).

18779881 is an equidigital number, since it uses as much as digits as its factorization.

18779881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 225792, while the sum is 49.

The square root of 18779881 is about 4333.5760060255. The cubic root of 18779881 is about 265.8056931743.

The spelling of 18779881 in words is "eighteen million, seven hundred seventy-nine thousand, eight hundred eighty-one".