121985309 has 4 divisors (see below), whose sum is σ = 122025504. Its totient is φ = 121945116.

The previous prime is 121985293. The next prime is 121985321. The reversal of 121985309 is 903589121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 121985309 - 2⁴ = 121985293 is a prime.

It is a super-2 number, since 2×121985309² = 29760831223650962, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121985009) 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, 15137 + ... + 21750.

It is an arithmetic number, because the mean of its divisors is an integer number (30506376).

Almost surely, 2^121985309 is an apocalyptic number.

It is an amenable number.

121985309 is a deficient number, since it is larger than the sum of its proper divisors (40195).

121985309 is an equidigital number, since it uses as much as digits as its factorization.

121985309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40194.

The product of its (nonzero) digits is 19440, while the sum is 38.

The square root of 121985309 is about 11044.6959668431. The cubic root of 121985309 is about 495.9476577722.

The spelling of 121985309 in words is "one hundred twenty-one million, nine hundred eighty-five thousand, three hundred nine".