643642363051321 has 16 divisors (see below), whose sum is σ = 670356360450000. Its totient is φ = 617230292498176.

The previous prime is 643642363051279. The next prime is 643642363051403. The reversal of 643642363051321 is 123150363246346.

It can be written as a sum of positive squares in 8 ways, for example, as 172240320929296 + 471402042122025 = 13124036^2 + 21711795^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643642363051321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643642363051021) 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, 51532575 + ... + 62792443.

It is an arithmetic number, because the mean of its divisors is an integer number (41897272528125).

Almost surely, 2^{643642363051321} is an apocalyptic number.

It is an amenable number.

643642363051321 is a deficient number, since it is larger than the sum of its proper divisors (26713997398679).

643642363051321 is a wasteful number, since it uses less digits than its factorization.

643642363051321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11273276.

The product of its (nonzero) digits is 5598720, while the sum is 49.

The spelling of 643642363051321 in words is "six hundred forty-three trillion, six hundred forty-two billion, three hundred sixty-three million, fifty-one thousand, three hundred twenty-one".