643242121045 has 4 divisors (see below), whose sum is σ = 771890545260. Its totient is φ = 514593696832.

The previous prime is 643242121037. The next prime is 643242121073. The reversal of 643242121045 is 540121242346.

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

It can be written as a sum of positive squares in 2 ways, for example, as 498348459844 + 144893661201 = 705938^2 + 380649^2 .

It is a cyclic number.

It is not a de Polignac number, because 643242121045 - 2³ = 643242121037 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 643242121045.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64324212100 + ... + 64324212109.

It is an arithmetic number, because the mean of its divisors is an integer number (192972636315).

Almost surely, 2^643242121045 is an apocalyptic number.

It is an amenable number.

643242121045 is a deficient number, since it is larger than the sum of its proper divisors (128648424215).

643242121045 is a wasteful number, since it uses less digits than its factorization.

643242121045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128648424214.

The product of its (nonzero) digits is 46080, while the sum is 34.

The spelling of 643242121045 in words is "six hundred forty-three billion, two hundred forty-two million, one hundred twenty-one thousand, forty-five".