1005978781 has 2 divisors, whose sum is σ = 1005978782. Its totient is φ = 1005978780.

The previous prime is 1005978751. The next prime is 1005978793. The reversal of 1005978781 is 1878795001.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 700078681 + 305900100 = 26459^2 + 17490^2 .

It is a cyclic number.

It is not a de Polignac number, because 1005978781 - 2⁹ = 1005978269 is a prime.

It is a super-2 number, since 2×1005978781² = 2023986615644491922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1005978751) 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, 502989390 + 502989391.

It is an arithmetic number, because the mean of its divisors is an integer number (502989391).

Almost surely, 2^1005978781 is an apocalyptic number.

It is an amenable number.

1005978781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1005978781 is an equidigital number, since it uses as much as digits as its factorization.

1005978781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 141120, while the sum is 46.

The square root of 1005978781 is about 31717.1685526940. The cubic root of 1005978781 is about 1001.9889683820.

The spelling of 1005978781 in words is "one billion, five million, nine hundred seventy-eight thousand, seven hundred eighty-one".