51021017040 has 320 divisors, whose sum is σ = 186786902016. Its totient is φ = 11278503936.

The previous prime is 51021017023. The next prime is 51021017041. The reversal of 51021017040 is 4071012015.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a junction number, because it is equal to n+sod(n) for n = 51021016998 and 51021017016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51021017041) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 7437292 + ... + 7444148.

Almost surely, 2^51021017040 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 51021017040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93393451008).

51021017040 is an abundant number, since it is smaller than the sum of its proper divisors (135765884976).

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

51021017040 is a wasteful number, since it uses less digits than its factorization.

51021017040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7026 (or 7020 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 21.

Adding to 51021017040 its reverse (4071012015), we get a palindrome (55092029055).

The spelling of 51021017040 in words is "fifty-one billion, twenty-one million, seventeen thousand, forty".