51244391640 has 128 divisors (see below), whose sum is σ = 166204301760. Its totient is φ = 12564824064.

The previous prime is 51244391629. The next prime is 51244391641. The reversal of 51244391640 is 4619344215.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51244391641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 337012 + ... + 464828.

Almost surely, 2^51244391640 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 51244391640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83102150880).

51244391640 is an abundant number, since it is smaller than the sum of its proper divisors (114959910120).

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

51244391640 is a wasteful number, since it uses less digits than its factorization.

51244391640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128101 (or 128097 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 39.

The spelling of 51244391640 in words is "fifty-one billion, two hundred forty-four million, three hundred ninety-one thousand, six hundred forty".