10643656721605 has 8 divisors (see below), whose sum is σ = 12772447396632. Its totient is φ = 8514885823488.

The previous prime is 10643656721591. The next prime is 10643656721611. The reversal of 10643656721605 is 50612765634601.

It can be written as a sum of positive squares in 4 ways, for example, as 523107920644 + 10120548800961 = 723262^2 + 3181281^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 10643656721605 - 2¹⁷ = 10643656590533 is a prime.

It is a super-2 number, since 2×10643656721605² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3733252 + ... + 5935021.

It is an arithmetic number, because the mean of its divisors is an integer number (1596555924579).

Almost surely, 2^{10643656721605} is an apocalyptic number.

It is an amenable number.

10643656721605 is a deficient number, since it is larger than the sum of its proper divisors (2128790675027).

10643656721605 is an equidigital number, since it uses as much as digits as its factorization.

10643656721605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9888455.

The product of its (nonzero) digits is 5443200, while the sum is 52.

The spelling of 10643656721605 in words is "ten trillion, six hundred forty-three billion, six hundred fifty-six million, seven hundred twenty-one thousand, six hundred five".