42991616 has 42 divisors (see below), whose sum is σ = 88080342. Its totient is φ = 20971520.

The previous prime is 42991609. The next prime is 42991621. The reversal of 42991616 is 61619924.

It can be written as a sum of positive squares in only one way, i.e., 26214400 + 16777216 = 5120^2 + 4096^2 .

Its product of digits (23328) is a multiple of the sum of its prime factors (81).

It is a nialpdrome in base 4.

It is a self number, because there is not a number n which added to its sum of digits gives 42991616.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (3) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1048556 + ... + 1048596.

It is an arithmetic number, because the mean of its divisors is an integer number (2097151).

Almost surely, 2^42991616 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 42991616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44040171).

42991616 is an abundant number, since it is smaller than the sum of its proper divisors (45088726).

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

42991616 is an frugal number, since it uses more digits than its factorization.

42991616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81 (or 43 counting only the distinct ones).

The product of its digits is 23328, while the sum is 38.

The square root of 42991616 is about 6556.7992191312. The cubic root of 42991616 is about 350.3170351871.

The spelling of 42991616 in words is "forty-two million, nine hundred ninety-one thousand, six hundred sixteen".