6630007781 has 4 divisors (see below), whose sum is σ = 6630195852. Its totient is φ = 6629819712.

The previous prime is 6630007757. The next prime is 6630007799. The reversal of 6630007781 is 1877000366.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2453617156 + 4176390625 = 49534^2 + 64625^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6630007781 is a prime.

It is a super-2 number, since 2×6630007781² = 87914006352241087922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6630007751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23540 + ... + 117533.

It is an arithmetic number, because the mean of its divisors is an integer number (1657548963).

Almost surely, 2^6630007781 is an apocalyptic number.

It is an amenable number.

6630007781 is a deficient number, since it is larger than the sum of its proper divisors (188071).

6630007781 is a wasteful number, since it uses less digits than its factorization.

6630007781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188070.

The product of its (nonzero) digits is 42336, while the sum is 38.

The square root of 6630007781 is about 81424.8597235513. The cubic root of 6630007781 is about 1878.6159819864.

The spelling of 6630007781 in words is "six billion, six hundred thirty million, seven thousand, seven hundred eighty-one".