1640404726 has 8 divisors (see below), whose sum is σ = 2465500464. Its totient is φ = 818571240.

The previous prime is 1640404723. The next prime is 1640404739. The reversal of 1640404726 is 6274040461.

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

It is a junction number, because it is equal to n+sod(n) for n = 1640404691 and 1640404700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640404723) 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 in 3 ways as a sum of consecutive naturals, for example, 814305 + ... + 816316.

It is an arithmetic number, because the mean of its divisors is an integer number (308187558).

Almost surely, 2^1640404726 is an apocalyptic number.

1640404726 is a deficient number, since it is larger than the sum of its proper divisors (825095738).

1640404726 is a wasteful number, since it uses less digits than its factorization.

1640404726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1631126.

The product of its (nonzero) digits is 32256, while the sum is 34.

The square root of 1640404726 is about 40501.9101524854. The cubic root of 1640404726 is about 1179.3707087002.

The spelling of 1640404726 in words is "one billion, six hundred forty million, four hundred four thousand, seven hundred twenty-six".