78261811 has 2 divisors, whose sum is σ = 78261812. Its totient is φ = 78261810.

The previous prime is 78261797. The next prime is 78261839. The reversal of 78261811 is 11816287.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78261811 - 2⁹ = 78261299 is a prime.

It is a super-2 number, since 2×78261811² = 12249822121999442, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78261871) 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 as a sum of consecutive naturals, namely, 39130905 + 39130906.

It is an arithmetic number, because the mean of its divisors is an integer number (39130906).

Almost surely, 2^78261811 is an apocalyptic number.

78261811 is a deficient number, since it is larger than the sum of its proper divisors (1).

78261811 is an equidigital number, since it uses as much as digits as its factorization.

78261811 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5376, while the sum is 34.

The square root of 78261811 is about 8846.5705784784. The cubic root of 78261811 is about 427.7433809015.

The spelling of 78261811 in words is "seventy-eight million, two hundred sixty-one thousand, eight hundred eleven".