641020251 has 4 divisors (see below), whose sum is σ = 854693672. Its totient is φ = 427346832.

The previous prime is 641020249. The next prime is 641020273. The reversal of 641020251 is 152020146.

641020251 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 641020251 - 2¹ = 641020249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (641020231) 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, 106836706 + ... + 106836711.

It is an arithmetic number, because the mean of its divisors is an integer number (213673418).

Almost surely, 2^641020251 is an apocalyptic number.

641020251 is a deficient number, since it is larger than the sum of its proper divisors (213673421).

641020251 is a wasteful number, since it uses less digits than its factorization.

641020251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213673420.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 641020251 is about 25318.3777323904. The cubic root of 641020251 is about 862.2315629234.

Adding to 641020251 its reverse (152020146), we get a palindrome (793040397).

The spelling of 641020251 in words is "six hundred forty-one million, twenty thousand, two hundred fifty-one".