641890069 has 4 divisors (see below), whose sum is σ = 644645196. Its totient is φ = 639134944.

The previous prime is 641890057. The next prime is 641890079. The reversal of 641890069 is 960098146.

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 438399844 + 203490225 = 20938^2 + 14265^2 .

It is a cyclic number.

It is not a de Polignac number, because 641890069 - 2⁵ = 641890037 is a prime.

It is a super-2 number, since 2×641890069² = 824045721361649522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641890009) 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, 1377214 + ... + 1377679.

It is an arithmetic number, because the mean of its divisors is an integer number (161161299).

Almost surely, 2^641890069 is an apocalyptic number.

It is an amenable number.

641890069 is a deficient number, since it is larger than the sum of its proper divisors (2755127).

641890069 is a wasteful number, since it uses less digits than its factorization.

641890069 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2755126.

The product of its (nonzero) digits is 93312, while the sum is 43.

The square root of 641890069 is about 25335.5495105198. The cubic root of 641890069 is about 862.6213818946.

The spelling of 641890069 in words is "six hundred forty-one million, eight hundred ninety thousand, sixty-nine".