1640780266 has 8 divisors (see below), whose sum is σ = 2494885284. Its totient is φ = 809151840.

The previous prime is 1640780261. The next prime is 1640780311. The reversal of 1640780266 is 6620870461.

It can be written as a sum of positive squares in 2 ways, for example, as 1639035225 + 1745041 = 40485^2 + 1321^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (1640780261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5618965 + ... + 5619256.

Almost surely, 2^1640780266 is an apocalyptic number.

1640780266 is a deficient number, since it is larger than the sum of its proper divisors (854105018).

1640780266 is a wasteful number, since it uses less digits than its factorization.

1640780266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11238296.

The product of its (nonzero) digits is 96768, while the sum is 40.

The square root of 1640780266 is about 40506.5459648191. The cubic root of 1640780266 is about 1179.4607001264.

It can be divided in two parts, 16 and 40780266, that multiplied together give a palindrome (652484256).

The spelling of 1640780266 in words is "one billion, six hundred forty million, seven hundred eighty thousand, two hundred sixty-six".