11666550138 has 64 divisors (see below), whose sum is σ = 23955540480. Its totient is φ = 3786754752.

The previous prime is 11666550127. The next prime is 11666550143. The reversal of 11666550138 is 83105566611.

It is a super-2 number, since 2×11666550138² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 11666550138.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 15786573 + ... + 15787311.

It is an arithmetic number, because the mean of its divisors is an integer number (374305320).

Almost surely, 2^11666550138 is an apocalyptic number.

11666550138 is an abundant number, since it is smaller than the sum of its proper divisors (12288990342).

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

11666550138 is a wasteful number, since it uses less digits than its factorization.

11666550138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1211.

The product of its (nonzero) digits is 129600, while the sum is 42.

The spelling of 11666550138 in words is "eleven billion, six hundred sixty-six million, five hundred fifty thousand, one hundred thirty-eight".