641655613 has 4 divisors (see below), whose sum is σ = 650693088. Its totient is φ = 632618140.

The previous prime is 641655607. The next prime is 641655629. The reversal of 641655613 is 316556146.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 316556146 = 2 ⋅158278073.

It is a cyclic number.

It is not a de Polignac number, because 641655613 - 2²¹ = 639558461 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 (641658613) 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, 4518631 + ... + 4518772.

It is an arithmetic number, because the mean of its divisors is an integer number (162673272).

Almost surely, 2^641655613 is an apocalyptic number.

It is an amenable number.

641655613 is a deficient number, since it is larger than the sum of its proper divisors (9037475).

641655613 is an equidigital number, since it uses as much as digits as its factorization.

641655613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9037474.

The product of its digits is 64800, while the sum is 37.

The square root of 641655613 is about 25330.9220716499. The cubic root of 641655613 is about 862.5163424195.

The spelling of 641655613 in words is "six hundred forty-one million, six hundred fifty-five thousand, six hundred thirteen".