7781881 has 2 divisors, whose sum is σ = 7781882. Its totient is φ = 7781880.

The previous prime is 7781863. The next prime is 7781897. The reversal of 7781881 is 1881877.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5363856 + 2418025 = 2316^2 + 1555^2 .

It is a cyclic number.

It is not a de Polignac number, because 7781881 - 2⁹ = 7781369 is a prime.

It is a super-2 number, since 2×7781881² = 121115343796322, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (7781821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3890940 + 3890941.

It is an arithmetic number, because the mean of its divisors is an integer number (3890941).

Almost surely, 2^7781881 is an apocalyptic number.

It is an amenable number.

7781881 is a deficient number, since it is larger than the sum of its proper divisors (1).

7781881 is an equidigital number, since it uses as much as digits as its factorization.

7781881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25088, while the sum is 40.

The square root of 7781881 is about 2789.6023014043. The cubic root of 7781881 is about 198.1655673945.

The spelling of 7781881 in words is "seven million, seven hundred eighty-one thousand, eight hundred eighty-one".