641766636421 has 8 divisors (see below), whose sum is σ = 679591569240. Its totient is φ = 603949920768.

The previous prime is 641766636419. The next prime is 641766636487. The reversal of 641766636421 is 124636667146.

641766636421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 9065705796 + 632700930625 = 95214^2 + 795425^2 .

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 641766636421 - 2¹ = 641766636419 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 (641766636491) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1893126 + ... + 2206231.

It is an arithmetic number, because the mean of its divisors is an integer number (84948946155).

Almost surely, 2^641766636421 is an apocalyptic number.

It is an amenable number.

641766636421 is a deficient number, since it is larger than the sum of its proper divisors (37824932819).

641766636421 is a wasteful number, since it uses less digits than its factorization.

641766636421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4108583.

The product of its digits is 5225472, while the sum is 52.

The spelling of 641766636421 in words is "six hundred forty-one billion, seven hundred sixty-six million, six hundred thirty-six thousand, four hundred twenty-one".