42778811 has 2 divisors, whose sum is σ = 42778812. Its totient is φ = 42778810.

The previous prime is 42778777. The next prime is 42778819. The reversal of 42778811 is 11887724.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42778811 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (42778819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21389405 + 21389406.

It is an arithmetic number, because the mean of its divisors is an integer number (21389406).

Almost surely, 2^42778811 is an apocalyptic number.

42778811 is a deficient number, since it is larger than the sum of its proper divisors (1).

42778811 is an equidigital number, since it uses as much as digits as its factorization.

42778811 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25088, while the sum is 38.

The square root of 42778811 is about 6540.5512764598. The cubic root of 42778811 is about 349.7380652453.

The spelling of 42778811 in words is "forty-two million, seven hundred seventy-eight thousand, eight hundred eleven".