121721997 has 8 divisors (see below), whose sum is σ = 162415744. Its totient is φ = 81088128.

The previous prime is 121721993. The next prime is 121722011. The reversal of 121721997 is 799127121.

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

It is not a de Polignac number, because 121721997 - 2² = 121721993 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 (121721993) 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, 9988 + ... + 18525.

It is an arithmetic number, because the mean of its divisors is an integer number (20301968).

Almost surely, 2^121721997 is an apocalyptic number.

It is an amenable number.

121721997 is a deficient number, since it is larger than the sum of its proper divisors (40693747).

121721997 is a wasteful number, since it uses less digits than its factorization.

121721997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29939.

The product of its digits is 15876, while the sum is 39.

The square root of 121721997 is about 11032.7692353280. The cubic root of 121721997 is about 495.5905572745.

The spelling of 121721997 in words is "one hundred twenty-one million, seven hundred twenty-one thousand, nine hundred ninety-seven".