643261115055 has 96 divisors (see below), whose sum is σ = 1141115576832. Its totient is φ = 307530558720.

The previous prime is 643261115053. The next prime is 643261115113. The reversal of 643261115055 is 550511162346.

It is not a de Polignac number, because 643261115055 - 2¹ = 643261115053 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643261115051) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 65855782 + ... + 65865548.

It is an arithmetic number, because the mean of its divisors is an integer number (11886620592).

Almost surely, 2^643261115055 is an apocalyptic number.

643261115055 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

643261115055 is a deficient number, since it is larger than the sum of its proper divisors (497854461777).

643261115055 is a wasteful number, since it uses less digits than its factorization.

643261115055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9997 (or 9926 counting only the distinct ones).

The product of its (nonzero) digits is 108000, while the sum is 39.

The spelling of 643261115055 in words is "six hundred forty-three billion, two hundred sixty-one million, one hundred fifteen thousand, fifty-five".