65638921869 has 6 divisors (see below), whose sum is σ = 94811776046. Its totient is φ = 43759281240.

The previous prime is 65638921861. The next prime is 65638921877. The reversal of 65638921869 is 96812983656.

65638921869 is a `hidden beast` number, since 6 + 563 + 8 + 9 + 2 + 1 + 8 + 69 = 666.

65638921869 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (65638921861) and next prime (65638921877).

It can be written as a sum of positive squares in only one way, i.e., 61724918025 + 3914003844 = 248445^2 + 62562^2 .

It is not a de Polignac number, because 65638921869 - 2³ = 65638921861 is a prime.

It is a super-2 number, since 2×65638921869² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65638921861) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3646606762 + ... + 3646606779.

Almost surely, 2^65638921869 is an apocalyptic number.

It is an amenable number.

65638921869 is a deficient number, since it is larger than the sum of its proper divisors (29172854177).

65638921869 is a wasteful number, since it uses less digits than its factorization.

65638921869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7293213547 (or 7293213544 counting only the distinct ones).

The product of its digits is 33592320, while the sum is 63.

The spelling of 65638921869 in words is "sixty-five billion, six hundred thirty-eight million, nine hundred twenty-one thousand, eight hundred sixty-nine".