66513986450 has 18 divisors (see below), whose sum is σ = 123719406879. Its totient is φ = 26604865120.

The previous prime is 66513986411. The next prime is 66513986459. The reversal of 66513986450 is 5468931566.

It is a happy number.

It can be written as a sum of positive squares in 5 ways, for example, as 16981477969 + 49532508481 = 130313^2 + 222559^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=182365.

It is a super-2 number, since 2×66513986450² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66513986392 and 66513986401.

It is not an unprimeable number, because it can be changed into a prime (66513986459) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1805414 + ... + 1841886.

Almost surely, 2^66513986450 is an apocalyptic number.

66513986450 is a deficient number, since it is larger than the sum of its proper divisors (57205420429).

66513986450 is an frugal number, since it uses more digits than its factorization.

66513986450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72958 (or 36480 counting only the distinct ones).

The product of its (nonzero) digits is 4665600, while the sum is 53.

The spelling of 66513986450 in words is "sixty-six billion, five hundred thirteen million, nine hundred eighty-six thousand, four hundred fifty".