51111955440 has 480 divisors, whose sum is σ = 211766196096. Its totient is φ = 10758389760.

The previous prime is 51111955399. The next prime is 51111955457. The reversal of 51111955440 is 4455911115.

It is a happy number.

51111955440 is a `hidden beast` number, since 5 + 11 + 11 + 95 + 544 + 0 = 666.

51111955440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×51111955440² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 51111955395 and 51111955404.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 41997712 + ... + 41998928.

Almost surely, 2^51111955440 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 51111955440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105883098048).

51111955440 is an abundant number, since it is smaller than the sum of its proper divisors (160654240656).

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

51111955440 is a wasteful number, since it uses less digits than its factorization.

51111955440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1897 (or 1888 counting only the distinct ones).

The product of its (nonzero) digits is 18000, while the sum is 36.

The spelling of 51111955440 in words is "fifty-one billion, one hundred eleven million, nine hundred fifty-five thousand, four hundred forty".