1640842840 has 128 divisors (see below), whose sum is σ = 4560312960. Its totient is φ = 517423104.

The previous prime is 1640842817. The next prime is 1640842867. The reversal of 1640842840 is 482480461.

It is a self number, because there is not a number n which added to its sum of digits gives 1640842840.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1284282 + ... + 1285558.

It is an arithmetic number, because the mean of its divisors is an integer number (35627445).

Almost surely, 2^1640842840 is an apocalyptic number.

1640842840 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 1640842840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2280156480).

1640842840 is an abundant number, since it is smaller than the sum of its proper divisors (2919470120).

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

1640842840 is a wasteful number, since it uses less digits than its factorization.

1640842840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1661 (or 1657 counting only the distinct ones).

The product of its (nonzero) digits is 49152, while the sum is 37.

The square root of 1640842840 is about 40507.3183511326. The cubic root of 1640842840 is about 1179.4756935286.

The spelling of 1640842840 in words is "one billion, six hundred forty million, eight hundred forty-two thousand, eight hundred forty".