1643500655 has 4 divisors (see below), whose sum is σ = 1972200792. Its totient is φ = 1314800520.

The previous prime is 1643500643. The next prime is 1643500667. The reversal of 1643500655 is 5560053461.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (1643500643) and next prime (1643500667).

It is not a de Polignac number, because 1643500655 - 2⁶ = 1643500591 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 164350061 + ... + 164350070.

It is an arithmetic number, because the mean of its divisors is an integer number (493050198).

Almost surely, 2^1643500655 is an apocalyptic number.

1643500655 is a deficient number, since it is larger than the sum of its proper divisors (328700137).

1643500655 is an equidigital number, since it uses as much as digits as its factorization.

1643500655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328700136.

The product of its (nonzero) digits is 54000, while the sum is 35.

The square root of 1643500655 is about 40540.1116796686. Note that the first 3 decimals coincide. The cubic root of 1643500655 is about 1180.1121829090.

The spelling of 1643500655 in words is "one billion, six hundred forty-three million, five hundred thousand, six hundred fifty-five".