1201819121 has 4 divisors (see below), whose sum is σ = 1202271744. Its totient is φ = 1201366500.

The previous prime is 1201819111. The next prime is 1201819127. The reversal of 1201819121 is 1219181021.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1219181021 = 43 ⋅28353047.

It is a cyclic number.

It is not a de Polignac number, because 1201819121 - 2¹⁸ = 1201556977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1201819127) 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, 222305 + ... + 227646.

It is an arithmetic number, because the mean of its divisors is an integer number (300567936).

Almost surely, 2^1201819121 is an apocalyptic number.

It is an amenable number.

1201819121 is a deficient number, since it is larger than the sum of its proper divisors (452623).

1201819121 is an equidigital number, since it uses as much as digits as its factorization.

1201819121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 452622.

The product of its (nonzero) digits is 288, while the sum is 26.

The square root of 1201819121 is about 34667.2629580127. The cubic root of 1201819121 is about 1063.1952715496.

The spelling of 1201819121 in words is "one billion, two hundred one million, eight hundred nineteen thousand, one hundred twenty-one".