51390493440 has 864 divisors, whose sum is σ = 202957622784. Its totient is φ = 10964828160.

The previous prime is 51390493423. The next prime is 51390493471. The reversal of 51390493440 is 4439409315.

51390493440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 51390493392 and 51390493401.

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, 164186724 + ... + 164187036.

It is an arithmetic number, because the mean of its divisors is an integer number (234904656).

Almost surely, 2^51390493440 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 51390493440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101478811392).

51390493440 is an abundant number, since it is smaller than the sum of its proper divisors (151567129344).

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

51390493440 is a wasteful number, since it uses less digits than its factorization.

51390493440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 397 (or 370 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 42.

The spelling of 51390493440 in words is "fifty-one billion, three hundred ninety million, four hundred ninety-three thousand, four hundred forty".