1640477664 has 144 divisors (see below), whose sum is σ = 5566050000. Its totient is φ = 468695808.

The previous prime is 1640477659. The next prime is 1640477687. The reversal of 1640477664 is 4667740461.

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

It is a congruent number.

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, 22962 + ... + 61710.

It is an arithmetic number, because the mean of its divisors is an integer number (38653125).

Almost surely, 2^1640477664 is an apocalyptic number.

1640477664 is a gapful number since it is divisible by the number (14) 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 1640477664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2783025000).

1640477664 is an abundant number, since it is smaller than the sum of its proper divisors (3925572336).

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

1640477664 is a wasteful number, since it uses less digits than its factorization.

1640477664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38782 (or 38761 counting only the distinct ones).

The product of its (nonzero) digits is 677376, while the sum is 45.

The square root of 1640477664 is about 40502.8105691445. The cubic root of 1640477664 is about 1179.3881880585.

The spelling of 1640477664 in words is "one billion, six hundred forty million, four hundred seventy-seven thousand, six hundred sixty-four".