1640422764 has 72 divisors (see below), whose sum is σ = 4254501888. Its totient is φ = 532691040.

The previous prime is 1640422759. The next prime is 1640422783. The reversal of 1640422764 is 4672240461.

1640422764 is a `hidden beast` number, since 1 + 640 + 4 + 2 + 2 + 7 + 6 + 4 = 666.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 381949 + ... + 386219.

It is an arithmetic number, because the mean of its divisors is an integer number (59090304).

Almost surely, 2^1640422764 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1640422764, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2127250944).

1640422764 is an abundant number, since it is smaller than the sum of its proper divisors (2614079124).

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

1640422764 is a wasteful number, since it uses less digits than its factorization.

1640422764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4555 (or 4550 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 36.

The square root of 1640422764 is about 40502.1328327287. The cubic root of 1640422764 is about 1179.3750314974.

The spelling of 1640422764 in words is "one billion, six hundred forty million, four hundred twenty-two thousand, seven hundred sixty-four".