1640319994 has 4 divisors (see below), whose sum is σ = 2460479994. Its totient is φ = 820159996.

The previous prime is 1640319983. The next prime is 1640319997. The reversal of 1640319994 is 4999130461.

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

It can be written as a sum of positive squares in only one way, i.e., 1324013769 + 316306225 = 36387^2 + 17785^2 .

It is not an unprimeable number, because it can be changed into a prime (1640319997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410079997 + ... + 410080000.

Almost surely, 2^1640319994 is an apocalyptic number.

1640319994 is a deficient number, since it is larger than the sum of its proper divisors (820160000).

1640319994 is an equidigital number, since it uses as much as digits as its factorization.

1640319994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 820159999.

The product of its (nonzero) digits is 209952, while the sum is 46.

The square root of 1640319994 is about 40500.8641142384. The cubic root of 1640319994 is about 1179.3504022970.

The spelling of 1640319994 in words is "one billion, six hundred forty million, three hundred nineteen thousand, nine hundred ninety-four".