661111199 has 4 divisors (see below), whose sum is σ = 755555664. Its totient is φ = 566666736.

The previous prime is 661111193. The next prime is 661111207. The reversal of 661111199 is 991111166.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661111199 is a prime.

661111199 is a strobogrammatic number because it is the same when read upside-down.

It is a Duffinian number.

It is a zygodrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661111193) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47222222 + ... + 47222235.

It is an arithmetic number, because the mean of its divisors is an integer number (188888916).

Almost surely, 2^661111199 is an apocalyptic number.

661111199 is a deficient number, since it is larger than the sum of its proper divisors (94444465).

661111199 is an equidigital number, since it uses as much as digits as its factorization.

661111199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94444464.

The product of its digits is 2916, while the sum is 35.

The square root of 661111199 is about 25712.0827433329. The cubic root of 661111199 is about 871.1471189671.

The spelling of 661111199 in words is "six hundred sixty-one million, one hundred eleven thousand, one hundred ninety-nine".