1640915687 has 4 divisors (see below), whose sum is σ = 1641736920. Its totient is φ = 1640094456.

The previous prime is 1640915663. The next prime is 1640915761. The reversal of 1640915687 is 7865190461.

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

It is a cyclic number.

It is not a de Polignac number, because 1640915687 - 2⁶ = 1640915623 is a prime.

It is a Duffinian number.

It is a zygodrome in base 5.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640915587) 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, 407612 + ... + 411617.

It is an arithmetic number, because the mean of its divisors is an integer number (410434230).

Almost surely, 2^1640915687 is an apocalyptic number.

1640915687 is a deficient number, since it is larger than the sum of its proper divisors (821233).

1640915687 is an equidigital number, since it uses as much as digits as its factorization.

1640915687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 821232.

The product of its (nonzero) digits is 362880, while the sum is 47.

The square root of 1640915687 is about 40508.2175243493. The cubic root of 1640915687 is about 1179.4931479718.

The spelling of 1640915687 in words is "one billion, six hundred forty million, nine hundred fifteen thousand, six hundred eighty-seven".