641685281 has 4 divisors (see below), whose sum is σ = 679431492. Its totient is φ = 603939072.

The previous prime is 641685277. The next prime is 641685287. The reversal of 641685281 is 182586146.

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 338228881 + 303456400 = 18391^2 + 17420^2 .

It is a cyclic number.

It is not a de Polignac number, because 641685281 - 2² = 641685277 is a prime.

It is a super-2 number, since 2×641685281² = 823519999704097922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (641685287) 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, 18873080 + ... + 18873113.

It is an arithmetic number, because the mean of its divisors is an integer number (169857873).

Almost surely, 2^641685281 is an apocalyptic number.

It is an amenable number.

641685281 is a deficient number, since it is larger than the sum of its proper divisors (37746211).

641685281 is a wasteful number, since it uses less digits than its factorization.

641685281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37746210.

The product of its digits is 92160, while the sum is 41.

The square root of 641685281 is about 25331.5076732515. The cubic root of 641685281 is about 862.5296355007.

The spelling of 641685281 in words is "six hundred forty-one million, six hundred eighty-five thousand, two hundred eighty-one".