51613635664 has 20 divisors (see below), whose sum is σ = 100007682804. Its totient is φ = 25805201408.

The previous prime is 51613635649. The next prime is 51613635673. The reversal of 51613635664 is 46653631615.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 6027969600 + 45585666064 = 77640^2 + 213508^2 .

It is a super-2 number, since 2×51613635664² (a number of 22 digits) contains 22 as substring.

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, 187344 + ... + 371920.

Almost surely, 2^51613635664 is an apocalyptic number.

It is an amenable number.

51613635664 is a deficient number, since it is larger than the sum of its proper divisors (48394047140).

51613635664 is a wasteful number, since it uses less digits than its factorization.

51613635664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202062 (or 202056 counting only the distinct ones).

The product of its digits is 1166400, while the sum is 46.

The spelling of 51613635664 in words is "fifty-one billion, six hundred thirteen million, six hundred thirty-five thousand, six hundred sixty-four".