66743440 has 40 divisors (see below), whose sum is σ = 155545848. Its totient is φ = 26634240.

The previous prime is 66743437. The next prime is 66743461. The reversal of 66743440 is 4434766.

It can be written as a sum of positive squares in 4 ways, for example, as 3254416 + 63489024 = 1804^2 + 7968^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Smith number, since the sum of its digits (34) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 66743396 and 66743405.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48360 + ... + 49720.

Almost surely, 2^66743440 is an apocalyptic number.

It is an amenable number.

66743440 is an abundant number, since it is smaller than the sum of its proper divisors (88802408).

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

66743440 is a wasteful number, since it uses less digits than its factorization.

66743440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1987 (or 1981 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 34.

The square root of 66743440 is about 8169.6658438396. The cubic root of 66743440 is about 405.6357236345.

The spelling of 66743440 in words is "sixty-six million, seven hundred forty-three thousand, four hundred forty".