1640609406 has 24 divisors (see below), whose sum is σ = 3555489600. Its totient is φ = 546741216.

The previous prime is 1640609381. The next prime is 1640609423. The reversal of 1640609406 is 6049060461.

1640609406 is a `hidden beast` number, since 1 + 6 + 4 + 0 + 609 + 40 + 6 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 97491 + ... + 113073.

It is an arithmetic number, because the mean of its divisors is an integer number (148145400).

Almost surely, 2^1640609406 is an apocalyptic number.

1640609406 is an abundant number, since it is smaller than the sum of its proper divisors (1914880194).

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

1640609406 is a wasteful number, since it uses less digits than its factorization.

1640609406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21440 (or 21437 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 1640609406 is about 40504.4368680766. The cubic root of 1640609406 is about 1179.4197582942.

Adding to 1640609406 its reverse (6049060461), we get a palindrome (7689669867).

The spelling of 1640609406 in words is "one billion, six hundred forty million, six hundred nine thousand, four hundred six".