70779781 has 2 divisors, whose sum is σ = 70779782. Its totient is φ = 70779780.

The previous prime is 70779757. The next prime is 70779803. The reversal of 70779781 is 18797707.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49702500 + 21077281 = 7050^2 + 4591^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-70779781 is a prime.

It is a super-2 number, since 2×70779781² = 10019554796815922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (70779701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35389890 + 35389891.

It is an arithmetic number, because the mean of its divisors is an integer number (35389891).

Almost surely, 2^70779781 is an apocalyptic number.

It is an amenable number.

70779781 is a deficient number, since it is larger than the sum of its proper divisors (1).

70779781 is an equidigital number, since it uses as much as digits as its factorization.

70779781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 172872, while the sum is 46.

The square root of 70779781 is about 8413.0720310716. The cubic root of 70779781 is about 413.6532157102.

The spelling of 70779781 in words is "seventy million, seven hundred seventy-nine thousand, seven hundred eighty-one".