1640987805 has 16 divisors (see below), whose sum is σ = 2661549120. Its totient is φ = 863203968.

The previous prime is 1640987797. The next prime is 1640987807. The reversal of 1640987805 is 5087890461.

It is not a de Polignac number, because 1640987805 - 2³ = 1640987797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640987807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 748215 + ... + 750404.

It is an arithmetic number, because the mean of its divisors is an integer number (166346820).

Almost surely, 2^1640987805 is an apocalyptic number.

1640987805 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1640987805 is a deficient number, since it is larger than the sum of its proper divisors (1020561315).

1640987805 is a wasteful number, since it uses less digits than its factorization.

1640987805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1498700.

The product of its (nonzero) digits is 483840, while the sum is 48.

The square root of 1640987805 is about 40509.1076796317. The cubic root of 1640987805 is about 1179.5104272347.

The spelling of 1640987805 in words is "one billion, six hundred forty million, nine hundred eighty-seven thousand, eight hundred five".