121720357 has 8 divisors (see below), whose sum is σ = 140596992. Its totient is φ = 104145600.

The previous prime is 121720331. The next prime is 121720369. The reversal of 121720357 is 753027121.

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 121720357 - 2¹⁹ = 121196069 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 (121720657) 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, 325269 + ... + 325642.

It is an arithmetic number, because the mean of its divisors is an integer number (17574624).

Almost surely, 2^121720357 is an apocalyptic number.

121720357 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

121720357 is a deficient number, since it is larger than the sum of its proper divisors (18876635).

121720357 is a wasteful number, since it uses less digits than its factorization.

121720357 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 650939.

The product of its (nonzero) digits is 2940, while the sum is 28.

The square root of 121720357 is about 11032.6949110360. The cubic root of 121720357 is about 495.5883315137.

Adding to 121720357 its reverse (753027121), we get a palindrome (874747478).

The spelling of 121720357 in words is "one hundred twenty-one million, seven hundred twenty thousand, three hundred fifty-seven".