641406965 has 4 divisors (see below), whose sum is σ = 769688364. Its totient is φ = 513125568.

The previous prime is 641406943. The next prime is 641406973. The reversal of 641406965 is 569604146.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 569604146 = 2 ⋅284802073.

It can be written as a sum of positive squares in 2 ways, for example, as 200448964 + 440958001 = 14158^2 + 20999^2 .

It is a cyclic number.

It is not a de Polignac number, because 641406965 - 2¹⁶ = 641341429 is a prime.

It is a super-2 number, since 2×641406965² = 822805789501022450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64140692 + ... + 64140701.

It is an arithmetic number, because the mean of its divisors is an integer number (192422091).

Almost surely, 2^641406965 is an apocalyptic number.

It is an amenable number.

641406965 is a deficient number, since it is larger than the sum of its proper divisors (128281399).

641406965 is a wasteful number, since it uses less digits than its factorization.

641406965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128281398.

The product of its (nonzero) digits is 155520, while the sum is 41.

The square root of 641406965 is about 25326.0136026182. The cubic root of 641406965 is about 862.4049167745.

The spelling of 641406965 in words is "six hundred forty-one million, four hundred six thousand, nine hundred sixty-five".