1640243640 has 384 divisors, whose sum is σ = 6183086400. Its totient is φ = 345784320.

The previous prime is 1640243639. The next prime is 1640243641. The reversal of 1640243640 is 463420461.

It is an interprime number because it is at equal distance from previous prime (1640243639) and next prime (1640243641).

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 = 1640243598 and 1640243607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640243641) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 6097426 + ... + 6097694.

Almost surely, 2^1640243640 is an apocalyptic number.

1640243640 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 1640243640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3091543200).

1640243640 is an abundant number, since it is smaller than the sum of its proper divisors (4542842760).

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

1640243640 is a wasteful number, since it uses less digits than its factorization.

1640243640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 375 (or 364 counting only the distinct ones).

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

The square root of 1640243640 is about 40499.9214814054. The cubic root of 1640243640 is about 1179.3321031199.

The spelling of 1640243640 in words is "one billion, six hundred forty million, two hundred forty-three thousand, six hundred forty".