1640235987 has 40 divisors (see below), whose sum is σ = 2652438096. Its totient is φ = 1004125248.

The previous prime is 1640235983. The next prime is 1640236067. The reversal of 1640235987 is 7895320461.

1640235987 is a `hidden beast` number, since 16 + 40 + 2 + 3 + 598 + 7 = 666.

1640235987 is digitally balanced in base 10, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1640235987 - 2² = 1640235983 is a prime.

1640235987 is strictly pandigital in base 10.

It is not an unprimeable number, because it can be changed into a prime (1640235983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 203488 + ... + 211394.

It is a 1-persistent number, because it is pandigital, but 2⋅1640235987 = 3280471974 is not.

Almost surely, 2^1640235987 is an apocalyptic number.

1640235987 is a deficient number, since it is larger than the sum of its proper divisors (1012202109).

1640235987 is a wasteful number, since it uses less digits than its factorization.

1640235987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8129 (or 8120 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The square root of 1640235987 is about 40499.8269996305. The cubic root of 1640235987 is about 1179.3302689529.

The spelling of 1640235987 in words is "one billion, six hundred forty million, two hundred thirty-five thousand, nine hundred eighty-seven".