51398820 has 192 divisors, whose sum is σ = 185068800. Its totient is φ = 11704320.

The previous prime is 51398807. The next prime is 51398833. The reversal of 51398820 is 2889315.

It is an interprime number because it is at equal distance from previous prime (51398807) and next prime (51398833).

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

It is a Saint-Exupery number, since it is equal to the product of the sides of a Pythagorean triangle: 509 × 459 × 220.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 100726 + ... + 101234.

It is an arithmetic number, because the mean of its divisors is an integer number (963900).

Almost surely, 2^51398820 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 51398820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92534400).

51398820 is an abundant number, since it is smaller than the sum of its proper divisors (133669980).

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

51398820 is a wasteful number, since it uses less digits than its factorization.

51398820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 555 (or 547 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 51398820 is about 7169.2970366696. The cubic root of 51398820 is about 371.8071320725.

The spelling of 51398820 in words is "fifty-one million, three hundred ninety-eight thousand, eight hundred twenty".