6658401965 has 4 divisors (see below), whose sum is σ = 7990082364. Its totient is φ = 5326721568.

The previous prime is 6658401961. The next prime is 6658401973. The reversal of 6658401965 is 5691048566.

It is a happy number.

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 4852236964 + 1806165001 = 69658^2 + 42499^2 .

It is a cyclic number.

It is not a de Polignac number, because 6658401965 - 2² = 6658401961 is a prime.

It is a super-2 number, since 2×6658401965² = 88668633455031722450, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6658401961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 665840192 + ... + 665840201.

It is an arithmetic number, because the mean of its divisors is an integer number (1997520591).

Almost surely, 2^6658401965 is an apocalyptic number.

It is an amenable number.

6658401965 is a deficient number, since it is larger than the sum of its proper divisors (1331680399).

6658401965 is a wasteful number, since it uses less digits than its factorization.

6658401965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1331680398.

The product of its (nonzero) digits is 1555200, while the sum is 50.

The square root of 6658401965 is about 81599.0316425385. The cubic root of 6658401965 is about 1881.2939979482.

The spelling of 6658401965 in words is "six billion, six hundred fifty-eight million, four hundred one thousand, nine hundred sixty-five".