1640293920 has 144 divisors (see below), whose sum is σ = 5611394880. Its totient is φ = 436326912.

The previous prime is 1640293903. The next prime is 1640293951. The reversal of 1640293920 is 293920461.

1640293920 is a `hidden beast` number, since 1 + 640 + 2 + 9 + 3 + 9 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 700111 + ... + 702449.

It is an arithmetic number, because the mean of its divisors is an integer number (38968020).

Almost surely, 2^1640293920 is an apocalyptic number.

1640293920 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 1640293920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2805697440).

1640293920 is an abundant number, since it is smaller than the sum of its proper divisors (3971100960).

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

1640293920 is a wasteful number, since it uses less digits than its factorization.

1640293920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2847 (or 2836 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 36.

The square root of 1640293920 is about 40500.5422185926. The cubic root of 1640293920 is about 1179.3441534054.

The spelling of 1640293920 in words is "one billion, six hundred forty million, two hundred ninety-three thousand, nine hundred twenty".