1640985408 has 168 divisors, whose sum is σ = 4838090400. Its totient is φ = 531588096.

The previous prime is 1640985383. The next prime is 1640985421. The reversal of 1640985408 is 8045890461.

1640985408 is a `hidden beast` number, since 16 + 4 + 0 + 98 + 540 + 8 = 666.

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, 3704035 + ... + 3704477.

Almost surely, 2^1640985408 is an apocalyptic number.

1640985408 is a gapful number since it is divisible by the number (18) 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 1640985408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2419045200).

1640985408 is an abundant number, since it is smaller than the sum of its proper divisors (3197104992).

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

1640985408 is a wasteful number, since it uses less digits than its factorization.

1640985408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 629 (or 616 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 45.

The square root of 1640985408 is about 40509.0780936817. The cubic root of 1640985408 is about 1179.5098529286.

The spelling of 1640985408 in words is "one billion, six hundred forty million, nine hundred eighty-five thousand, four hundred eight".