641254981 has 4 divisors (see below), whose sum is σ = 654898752. Its totient is φ = 627611212.

The previous prime is 641254967. The next prime is 641254987. The reversal of 641254981 is 189452146.

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.

It is a cyclic number.

It is not a de Polignac number, because 641254981 - 2⁵ = 641254949 is a prime.

It is a super-2 number, since 2×641254981² = 822415901314620722, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641254987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6821815 + ... + 6821908.

It is an arithmetic number, because the mean of its divisors is an integer number (163724688).

Almost surely, 2^641254981 is an apocalyptic number.

It is an amenable number.

641254981 is a deficient number, since it is larger than the sum of its proper divisors (13643771).

641254981 is a wasteful number, since it uses less digits than its factorization.

641254981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13643770.

The product of its digits is 69120, while the sum is 40.

The square root of 641254981 is about 25323.0128736689. The cubic root of 641254981 is about 862.3367946045.

The spelling of 641254981 in words is "six hundred forty-one million, two hundred fifty-four thousand, nine hundred eighty-one".