55131780 has 96 divisors (see below), whose sum is σ = 170247168. Its totient is φ = 13219200.

The previous prime is 55131779. The next prime is 55131823. The reversal of 55131780 is 8713155.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 67575 + ... + 68385.

It is an arithmetic number, because the mean of its divisors is an integer number (1773408).

Almost surely, 2^55131780 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 55131780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85123584).

55131780 is an abundant number, since it is smaller than the sum of its proper divisors (115115388).

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

55131780 is a wasteful number, since it uses less digits than its factorization.

55131780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 937 (or 935 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 30.

The square root of 55131780 is about 7425.0777773704. The cubic root of 55131780 is about 380.5987329567.

The spelling of 55131780 in words is "fifty-five million, one hundred thirty-one thousand, seven hundred eighty".