66523440 has 80 divisors (see below), whose sum is σ = 209102688. Its totient is φ = 17491968.

The previous prime is 66523423. The next prime is 66523453. The reversal of 66523440 is 4432566.

66523440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 (30).

It is a junction number, because it is equal to n+sod(n) for n = 66523398 and 66523407.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15622 + ... + 19418.

Almost surely, 2^66523440 is an apocalyptic number.

66523440 is a gapful number since it is divisible by the number (60) 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 66523440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104551344).

66523440 is an abundant number, since it is smaller than the sum of its proper divisors (142579248).

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

66523440 is a wasteful number, since it uses less digits than its factorization.

66523440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3886 (or 3880 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 30.

The square root of 66523440 is about 8156.1902871377. The cubic root of 66523440 is about 405.1895470011.

The spelling of 66523440 in words is "sixty-six million, five hundred twenty-three thousand, four hundred forty".