661111100 has 54 divisors (see below), whose sum is σ = 1553494320. Its totient is φ = 244096320.

The previous prime is 661111097. The next prime is 661111123. The reversal of 661111100 is 1111166.

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 2660 + ... + 36459.

Almost surely, 2^661111100 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661111100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (776747160).

661111100 is an abundant number, since it is smaller than the sum of its proper divisors (892383220).

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

661111100 is a wasteful number, since it uses less digits than its factorization.

661111100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39159 (or 39139 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 17.

The square root of 661111100 is about 25712.0808181679. The cubic root of 661111100 is about 871.1470754830.

Adding to 661111100 its reverse (1111166), we get a palindrome (662222266).

The spelling of 661111100 in words is "six hundred sixty-one million, one hundred eleven thousand, one hundred".