121955865 has 8 divisors (see below), whose sum is σ = 195129408. Its totient is φ = 65043120.

The previous prime is 121955863. The next prime is 121955887. The reversal of 121955865 is 568559121.

It is a happy number.

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

It is not a de Polignac number, because 121955865 - 2¹ = 121955863 is a prime.

It is not an unprimeable number, because it can be changed into a prime (121955863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4065181 + ... + 4065210.

It is an arithmetic number, because the mean of its divisors is an integer number (24391176).

Almost surely, 2^121955865 is an apocalyptic number.

121955865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

121955865 is a deficient number, since it is larger than the sum of its proper divisors (73173543).

121955865 is an equidigital number, since it uses as much as digits as its factorization.

121955865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8130399.

The product of its digits is 108000, while the sum is 42.

The square root of 121955865 is about 11043.3629388878. The cubic root of 121955865 is about 495.9077517157.

The spelling of 121955865 in words is "one hundred twenty-one million, nine hundred fifty-five thousand, eight hundred sixty-five".