1640432640 has 704 divisors, whose sum is σ = 6980106240. Its totient is φ = 318504960.

The previous prime is 1640432617. The next prime is 1640432653. The reversal of 1640432640 is 462340461.

It is a tau number, because it is divible by the number of its divisors (704).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 1640432598 and 1640432607.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 22471644 + ... + 22471716.

Almost surely, 2^1640432640 is an apocalyptic number.

1640432640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1640432640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3490053120).

1640432640 is an abundant number, since it is smaller than the sum of its proper divisors (5339673600).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1640432640 is a wasteful number, since it uses less digits than its factorization.

1640432640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138 (or 120 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 30.

The square root of 1640432640 is about 40502.2547520505. The cubic root of 1640432640 is about 1179.3773982622.

The spelling of 1640432640 in words is "one billion, six hundred forty million, four hundred thirty-two thousand, six hundred forty".