42780 has 48 divisors (see below), whose sum is σ = 129024. Its totient is φ = 10560.

The previous prime is 42773. The next prime is 42787. The reversal of 42780 is 8724.

It is a happy number.

42780 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

42780 is an esthetic number in base 8, because in such base its adjacent digits differ by 1.

It is an interprime number because it is at equal distance from previous prime (42773) and next prime (42787).

It is a Smith number, since the sum of its digits (21) coincides with the sum of the digits of its prime factors.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42787) by changing a digit.

42780 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1365 + ... + 1395.

It is an arithmetic number, because the mean of its divisors is an integer number (2688).

2⁴²⁷⁸⁰ 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 42780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (64512).

42780 is an abundant number, since it is smaller than the sum of its proper divisors (86244).

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

42780 is a wasteful number, since it uses less digits than its factorization.

42780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66 (or 64 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 21.

The square root of 42780 is about 206.8332661832. The cubic root of 42780 is about 34.9741305438.

The spelling of 42780 in words is "forty-two thousand, seven hundred eighty".