66561128938 has 8 divisors (see below), whose sum is σ = 99842965632. Its totient is φ = 33280140396.

The previous prime is 66561128927. The next prime is 66561128981. The reversal of 66561128938 is 83982116566.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×66561128938² (a number of 22 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47881 + ... + 367987.

It is an arithmetic number, because the mean of its divisors is an integer number (12480370704).

Almost surely, 2^66561128938 is an apocalyptic number.

66561128938 is a deficient number, since it is larger than the sum of its proper divisors (33281836694).

66561128938 is a wasteful number, since it uses less digits than its factorization.

66561128938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424076.

The product of its digits is 3732480, while the sum is 55.

The spelling of 66561128938 in words is "sixty-six billion, five hundred sixty-one million, one hundred twenty-eight thousand, nine hundred thirty-eight".