121025809 has 4 divisors (see below), whose sum is σ = 123977700. Its totient is φ = 118073920.

The previous prime is 121025797. The next prime is 121025843. The reversal of 121025809 is 908520121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 42614784 + 78411025 = 6528^2 + 8855^2 .

It is a cyclic number.

It is not a de Polignac number, because 121025809 - 2⁵ = 121025777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121025909) 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, 1475884 + ... + 1475965.

It is an arithmetic number, because the mean of its divisors is an integer number (30994425).

Almost surely, 2^121025809 is an apocalyptic number.

It is an amenable number.

121025809 is a deficient number, since it is larger than the sum of its proper divisors (2951891).

121025809 is an equidigital number, since it uses as much as digits as its factorization.

121025809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2951890.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 121025809 is about 11001.1730738135. The cubic root of 121025809 is about 494.6439080978.

The spelling of 121025809 in words is "one hundred twenty-one million, twenty-five thousand, eight hundred nine".