1640413778 has 8 divisors (see below), whose sum is σ = 2466947340. Its totient is φ = 818098000.

The previous prime is 1640413777. The next prime is 1640413799. The reversal of 1640413778 is 8773140461.

It can be written as a sum of positive squares in 2 ways, for example, as 1639197169 + 1216609 = 40487^2 + 1103^2 .

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 (1640413777) 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, 1053473 + ... + 1055028.

Almost surely, 2^1640413778 is an apocalyptic number.

1640413778 is a deficient number, since it is larger than the sum of its proper divisors (826533562).

1640413778 is a wasteful number, since it uses less digits than its factorization.

1640413778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2108892.

The product of its (nonzero) digits is 112896, while the sum is 41.

The square root of 1640413778 is about 40502.0219001472. The cubic root of 1640413778 is about 1179.3728780112.

The spelling of 1640413778 in words is "one billion, six hundred forty million, four hundred thirteen thousand, seven hundred seventy-eight".