42991784 has 48 divisors (see below), whose sum is σ = 92504160. Its totient is φ = 18682400.

The previous prime is 42991783. The next prime is 42991789. The reversal of 42991784 is 48719924.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is not an unprimeable number, because it can be changed into a prime (42991783) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21299 + ... + 23229.

It is an arithmetic number, because the mean of its divisors is an integer number (1927170).

Almost surely, 2^42991784 is an apocalyptic number.

42991784 is a gapful number since it is divisible by the number (44) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 42991784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46252080).

42991784 is an abundant number, since it is smaller than the sum of its proper divisors (49512376).

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

42991784 is a wasteful number, since it uses less digits than its factorization.

42991784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1982 (or 1967 counting only the distinct ones).

The product of its digits is 145152, while the sum is 44.

The square root of 42991784 is about 6556.8120302476. The cubic root of 42991784 is about 350.3174915023.

The spelling of 42991784 in words is "forty-two million, nine hundred ninety-one thousand, seven hundred eighty-four".