121657121 has 4 divisors (see below), whose sum is σ = 121785732. Its totient is φ = 121528512.

The previous prime is 121657099. The next prime is 121657139. The reversal of 121657121 is 121756121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 121756121 = 4219 ⋅28859.

It can be written as a sum of positive squares in 2 ways, for example, as 17106496 + 104550625 = 4136^2 + 10225^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121657121 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (121617121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62876 + ... + 64781.

It is an arithmetic number, because the mean of its divisors is an integer number (30446433).

Almost surely, 2^121657121 is an apocalyptic number.

It is an amenable number.

121657121 is a deficient number, since it is larger than the sum of its proper divisors (128611).

121657121 is an equidigital number, since it uses as much as digits as its factorization.

121657121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128610.

The product of its digits is 840, while the sum is 26.

The square root of 121657121 is about 11029.8286931393. The cubic root of 121657121 is about 495.5024941809.

The spelling of 121657121 in words is "one hundred twenty-one million, six hundred fifty-seven thousand, one hundred twenty-one".