18757875781 has 2 divisors, whose sum is σ = 18757875782. Its totient is φ = 18757875780.

The previous prime is 18757875707. The next prime is 18757875863.

It is a happy number.

18757875781 is nontrivially palindromic in base 10.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12935422756 + 5822453025 = 113734^2 + 76305^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 18757875781 - 2¹³ = 18757867589 is a prime.

It is a super-2 number, since 2×18757875781² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18757875181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9378937890 + 9378937891.

It is an arithmetic number, because the mean of its divisors is an integer number (9378937891).

Almost surely, 2^18757875781 is an apocalyptic number.

It is an amenable number.

18757875781 is a deficient number, since it is larger than the sum of its proper divisors (1).

18757875781 is an equidigital number, since it uses as much as digits as its factorization.

18757875781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30732800, while the sum is 64.

The spelling of 18757875781 in words is "eighteen billion, seven hundred fifty-seven million, eight hundred seventy-five thousand, seven hundred eighty-one".