1640237905 has 8 divisors (see below), whose sum is σ = 2005423272. Its totient is φ = 1287431808.

The previous prime is 1640237897. The next prime is 1640237917. The reversal of 1640237905 is 5097320461.

It can be written as a sum of positive squares in 4 ways, for example, as 799701841 + 840536064 = 28279^2 + 28992^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 1640237905 - 2³ = 1640237897 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3094524 + ... + 3095053.

It is an arithmetic number, because the mean of its divisors is an integer number (250677909).

Almost surely, 2^1640237905 is an apocalyptic number.

It is an amenable number.

1640237905 is a deficient number, since it is larger than the sum of its proper divisors (365185367).

1640237905 is an equidigital number, since it uses as much as digits as its factorization.

1640237905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6189635.

The product of its (nonzero) digits is 45360, while the sum is 37.

The square root of 1640237905 is about 40499.8506787371. The cubic root of 1640237905 is about 1179.3307286336.

The spelling of 1640237905 in words is "one billion, six hundred forty million, two hundred thirty-seven thousand, nine hundred five".