42523440 has 80 divisors (see below), whose sum is σ = 132753408. Its totient is φ = 11259648.

The previous prime is 42523433. The next prime is 42523451. The reversal of 42523440 is 4432524.

It is a Cunningham number, because it is equal to 6521²-1.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 42523440.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38577 + ... + 39663.

Almost surely, 2^42523440 is an apocalyptic number.

42523440 is a gapful number since it is divisible by the number (40) 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 42523440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (66376704).

42523440 is an abundant number, since it is smaller than the sum of its proper divisors (90229968).

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

42523440 is a wasteful number, since it uses less digits than its factorization.

42523440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1266 (or 1260 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 24.

The square root of 42523440 is about 6520.9999233246. Note that the first 4 decimals coincide. The cubic root of 42523440 is about 349.0407475076.

Adding to 42523440 its reverse (4432524), we get a palindrome (46955964).

The spelling of 42523440 in words is "forty-two million, five hundred twenty-three thousand, four hundred forty".