1640163780 has 72 divisors (see below), whose sum is σ = 5005046592. Its totient is φ = 434750016.

The previous prime is 1640163761. The next prime is 1640163821. The reversal of 1640163780 is 873610461.

1640163780 is a `hidden beast` number, since 1 + 640 + 1 + 6 + 3 + 7 + 8 + 0 = 666.

It is a super-3 number, since 3×1640163780³ (a number of 29 digits) contains 333 as substring.

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, 2779 + ... + 57341.

It is an arithmetic number, because the mean of its divisors is an integer number (69514536).

Almost surely, 2^1640163780 is an apocalyptic number.

1640163780 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 1640163780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2502523296).

1640163780 is an abundant number, since it is smaller than the sum of its proper divisors (3364882812).

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

1640163780 is a wasteful number, since it uses less digits than its factorization.

1640163780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54745 (or 54740 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 1640163780 is about 40498.9355415670. The cubic root of 1640163780 is about 1179.3129630792.

The spelling of 1640163780 in words is "one billion, six hundred forty million, one hundred sixty-three thousand, seven hundred eighty".