1640443655 has 16 divisors (see below), whose sum is σ = 2023354080. Its totient is φ = 1275864192.

The previous prime is 1640443631. The next prime is 1640443657. The reversal of 1640443655 is 5563440461.

It is not a de Polignac number, because 1640443655 - 2¹⁶ = 1640378119 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640443657) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 296777 + ... + 302253.

It is an arithmetic number, because the mean of its divisors is an integer number (126459630).

Almost surely, 2^1640443655 is an apocalyptic number.

1640443655 is a deficient number, since it is larger than the sum of its proper divisors (382910425).

1640443655 is a wasteful number, since it uses less digits than its factorization.

1640443655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7138.

The product of its (nonzero) digits is 172800, while the sum is 38.

The square root of 1640443655 is about 40502.3907319062. The cubic root of 1640443655 is about 1179.3800379750.

The spelling of 1640443655 in words is "one billion, six hundred forty million, four hundred forty-three thousand, six hundred fifty-five".