667776644 has 6 divisors (see below), whose sum is σ = 1168609134. Its totient is φ = 333888320.

The previous prime is 667776623. The next prime is 667776647. The reversal of 667776644 is 446677766.

It can be written as a sum of positive squares in only one way, i.e., 615040000 + 52736644 = 24800^2 + 7262^2 .

It is a super-3 number, since 3×667776644³ (a number of 27 digits) contains 333 as substring.

It is a zygodrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (667776647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83472077 + ... + 83472084.

It is an arithmetic number, because the mean of its divisors is an integer number (194768189).

Almost surely, 2^667776644 is an apocalyptic number.

It is an amenable number.

667776644 is a deficient number, since it is larger than the sum of its proper divisors (500832490).

667776644 is a wasteful number, since it uses less digits than its factorization.

667776644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166944165 (or 166944163 counting only the distinct ones).

The product of its digits is 7112448, while the sum is 53.

The square root of 667776644 is about 25841.3746538376. The cubic root of 667776644 is about 874.0650231686.

The spelling of 667776644 in words is "six hundred sixty-seven million, seven hundred seventy-six thousand, six hundred forty-four".