661211117 has 8 divisors (see below), whose sum is σ = 764774976. Its totient is φ = 559923552.

The previous prime is 661211081. The next prime is 661211179. The reversal of 661211117 is 711112166.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 661211117 - 2⁸ = 661210861 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661211197) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 568448 + ... + 569609.

It is an arithmetic number, because the mean of its divisors is an integer number (95596872).

Almost surely, 2^661211117 is an apocalyptic number.

It is an amenable number.

661211117 is a deficient number, since it is larger than the sum of its proper divisors (103563859).

661211117 is a wasteful number, since it uses less digits than its factorization.

661211117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1138147.

The product of its digits is 504, while the sum is 26.

The square root of 661211117 is about 25714.0256863837. The cubic root of 661211117 is about 871.1910041175.

The spelling of 661211117 in words is "six hundred sixty-one million, two hundred eleven thousand, one hundred seventeen".