621671661013 has 4 divisors (see below), whose sum is σ = 669492558028. Its totient is φ = 573850764000.

The previous prime is 621671661007. The next prime is 621671661047. The reversal of 621671661013 is 310166176126.

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 369690752484 + 251980908529 = 608022^2 + 501977^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-621671661013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621671661313) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23910448488 + ... + 23910448513.

It is an arithmetic number, because the mean of its divisors is an integer number (167373139507).

Almost surely, 2^621671661013 is an apocalyptic number.

It is an amenable number.

621671661013 is a deficient number, since it is larger than the sum of its proper divisors (47820897015).

621671661013 is a wasteful number, since it uses less digits than its factorization.

621671661013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47820897014.

The product of its (nonzero) digits is 54432, while the sum is 40.

The spelling of 621671661013 in words is "six hundred twenty-one billion, six hundred seventy-one million, six hundred sixty-one thousand, thirteen".