51665155440 has 160 divisors (see below), whose sum is σ = 161887424256. Its totient is φ = 13629327360.

The previous prime is 51665155393. The next prime is 51665155541. The reversal of 51665155440 is 4455156615.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 51665155392 and 51665155401.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 33922519 + ... + 33924041.

Almost surely, 2^51665155440 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51665155440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (80943712128).

51665155440 is an abundant number, since it is smaller than the sum of its proper divisors (110222268816).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51665155440 is a wasteful number, since it uses less digits than its factorization.

51665155440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2967 (or 2961 counting only the distinct ones).

The product of its (nonzero) digits is 360000, while the sum is 42.

The spelling of 51665155440 in words is "fifty-one billion, six hundred sixty-five million, one hundred fifty-five thousand, four hundred forty".