30121819891 has 4 divisors (see below), whose sum is σ = 30124753792. Its totient is φ = 30118885992.

The previous prime is 30121819831. The next prime is 30121819909. The reversal of 30121819891 is 19891812103.

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

It is a cyclic number.

It is not a de Polignac number, because 30121819891 - 2²⁹ = 29584948979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (30121819811) 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, 1451496 + ... + 1472101.

It is an arithmetic number, because the mean of its divisors is an integer number (7531188448).

Almost surely, 2^30121819891 is an apocalyptic number.

30121819891 is a deficient number, since it is larger than the sum of its proper divisors (2933901).

30121819891 is a wasteful number, since it uses less digits than its factorization.

30121819891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2933900.

The product of its (nonzero) digits is 31104, while the sum is 43.

The spelling of 30121819891 in words is "thirty billion, one hundred twenty-one million, eight hundred nineteen thousand, eight hundred ninety-one".