51155780 has 48 divisors (see below), whose sum is σ = 116546304. Its totient is φ = 18748800.

The previous prime is 51155779. The next prime is 51155807. The reversal of 51155780 is 8755115.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38609 + ... + 39911.

It is an arithmetic number, because the mean of its divisors is an integer number (2428048).

Almost surely, 2^51155780 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 51155780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (58273152).

51155780 is an abundant number, since it is smaller than the sum of its proper divisors (65390524).

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

51155780 is a wasteful number, since it uses less digits than its factorization.

51155780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1476 (or 1474 counting only the distinct ones).

The product of its (nonzero) digits is 7000, while the sum is 32.

The square root of 51155780 is about 7152.3268940954. The cubic root of 51155780 is about 371.2201743055.

The spelling of 51155780 in words is "fifty-one million, one hundred fifty-five thousand, seven hundred eighty".