121505865 has 16 divisors (see below), whose sum is σ = 209364288. Its totient is φ = 59818176.

The previous prime is 121505863. The next prime is 121505887. The reversal of 121505865 is 568505121.

It is not a de Polignac number, because 121505865 - 2¹ = 121505863 is a prime.

It is not an unprimeable number, because it can be changed into a prime (121505861) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 311359 + ... + 311748.

It is an arithmetic number, because the mean of its divisors is an integer number (13085268).

Almost surely, 2^121505865 is an apocalyptic number.

121505865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

121505865 is a deficient number, since it is larger than the sum of its proper divisors (87858423).

121505865 is a wasteful number, since it uses less digits than its factorization.

121505865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 623128.

The product of its (nonzero) digits is 12000, while the sum is 33.

The square root of 121505865 is about 11022.9698811164. The cubic root of 121505865 is about 495.2970566723.

The spelling of 121505865 in words is "one hundred twenty-one million, five hundred five thousand, eight hundred sixty-five".