7838812661 has 2 divisors, whose sum is σ = 7838812662. Its totient is φ = 7838812660.

The previous prime is 7838812649. The next prime is 7838812687. The reversal of 7838812661 is 1662188387.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5375675761 + 2463136900 = 73319^2 + 49630^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7838812661 is a prime.

It is a super-2 number, since 2×7838812661² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7838811661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3919406330 + 3919406331.

It is an arithmetic number, because the mean of its divisors is an integer number (3919406331).

Almost surely, 2^7838812661 is an apocalyptic number.

It is an amenable number.

7838812661 is a deficient number, since it is larger than the sum of its proper divisors (1).

7838812661 is an equidigital number, since it uses as much as digits as its factorization.

7838812661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 774144, while the sum is 50.

The square root of 7838812661 is about 88537.0694172785. The cubic root of 7838812661 is about 1986.4764851273.

The spelling of 7838812661 in words is "seven billion, eight hundred thirty-eight million, eight hundred twelve thousand, six hundred sixty-one".