661161066550 has 24 divisors (see below), whose sum is σ = 1239442742016. Its totient is φ = 262382027040.

The previous prime is 661161066529. The next prime is 661161066557. The reversal of 661161066550 is 55660161166.

It is a junction number, because it is equal to n+sod(n) for n = 661161066497 and 661161066506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661161066557) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 52053577 + ... + 52066276.

It is an arithmetic number, because the mean of its divisors is an integer number (51643447584).

Almost surely, 2^661161066550 is an apocalyptic number.

661161066550 is a deficient number, since it is larger than the sum of its proper divisors (578281675466).

661161066550 is a wasteful number, since it uses less digits than its factorization.

661161066550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104119992 (or 104119987 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 43.

The spelling of 661161066550 in words is "six hundred sixty-one billion, one hundred sixty-one million, sixty-six thousand, five hundred fifty".