121905819 has 24 divisors (see below), whose sum is σ = 209993472. Its totient is φ = 66630960.

The previous prime is 121905803. The next prime is 121905829. The reversal of 121905819 is 918509121.

It is not a de Polignac number, because 121905819 - 2⁴ = 121905803 is a prime.

It is a super-2 number, since 2×121905819² = 29722057412121522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (121905829) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 40617 + ... + 43514.

It is an arithmetic number, because the mean of its divisors is an integer number (8749728).

Almost surely, 2^121905819 is an apocalyptic number.

121905819 is a deficient number, since it is larger than the sum of its proper divisors (88087653).

121905819 is a wasteful number, since it uses less digits than its factorization.

121905819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84167 (or 84164 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 36.

The square root of 121905819 is about 11041.0968205156. The cubic root of 121905819 is about 495.8399086073.

The spelling of 121905819 in words is "one hundred twenty-one million, nine hundred five thousand, eight hundred nineteen".