51379920 has 140 divisors (see below), whose sum is σ = 179308836. Its totient is φ = 13685760.

The previous prime is 51379919. The next prime is 51379921. The reversal of 51379920 is 2997315.

It is an interprime number because it is at equal distance from previous prime (51379919) and next prime (51379921).

It can be written as a sum of positive squares in 2 ways, for example, as 13483584 + 37896336 = 3672^2 + 6156^2 .

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

It is a zygodrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51379921) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 57880 + ... + 58760.

Almost surely, 2^51379920 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 51379920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89654418).

51379920 is an abundant number, since it is smaller than the sum of its proper divisors (127928916).

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

51379920 is an equidigital number, since it uses as much as digits as its factorization.

51379920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 912 (or 891 counting only the distinct ones).

The product of its (nonzero) digits is 17010, while the sum is 36.

The square root of 51379920 is about 7167.9787946115. The cubic root of 51379920 is about 371.7615537480.

The spelling of 51379920 in words is "fifty-one million, three hundred seventy-nine thousand, nine hundred twenty".