66291895840 has 48 divisors (see below), whose sum is σ = 157224096792. Its totient is φ = 26413563904.

The previous prime is 66291895823. The next prime is 66291895849. The reversal of 66291895840 is 4859819266.

66291895840 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 66260937744 + 30958096 = 257412^2 + 5564^2 .

It is a super-2 number, since 2×66291895840² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66291895849) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 764959 + ... + 847198.

Almost surely, 2^66291895840 is an apocalyptic number.

It is an amenable number.

66291895840 is an abundant number, since it is smaller than the sum of its proper divisors (90932200952).

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

66291895840 is a wasteful number, since it uses less digits than its factorization.

66291895840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1612429 (or 1612421 counting only the distinct ones).

The product of its (nonzero) digits is 7464960, while the sum is 58.

The spelling of 66291895840 in words is "sixty-six billion, two hundred ninety-one million, eight hundred ninety-five thousand, eight hundred forty".