121666511 has 4 divisors (see below), whose sum is σ = 122096712. Its totient is φ = 121236312.

The previous prime is 121666507. The next prime is 121666541. The reversal of 121666511 is 115666121.

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

It is a cyclic number.

It is not a de Polignac number, because 121666511 - 2² = 121666507 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121666541) 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, 214676 + ... + 215241.

It is an arithmetic number, because the mean of its divisors is an integer number (30524178).

Almost surely, 2^121666511 is an apocalyptic number.

121666511 is a deficient number, since it is larger than the sum of its proper divisors (430201).

121666511 is an equidigital number, since it uses as much as digits as its factorization.

121666511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 430200.

The product of its digits is 2160, while the sum is 29.

The square root of 121666511 is about 11030.2543488353. The cubic root of 121666511 is about 495.5152421639.

The spelling of 121666511 in words is "one hundred twenty-one million, six hundred sixty-six thousand, five hundred eleven".