1201636121 has 4 divisors (see below), whose sum is σ = 1373298432. Its totient is φ = 1029973812.

The previous prime is 1201636099. The next prime is 1201636187. The reversal of 1201636121 is 1216361021.

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: 1216361021 = 151 ⋅8055371.

It is not a de Polignac number, because 1201636121 - 2¹⁸ = 1201373977 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1201635121) 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, 85831145 + ... + 85831158.

It is an arithmetic number, because the mean of its divisors is an integer number (343324608).

Almost surely, 2^1201636121 is an apocalyptic number.

It is an amenable number.

1201636121 is a deficient number, since it is larger than the sum of its proper divisors (171662311).

1201636121 is an equidigital number, since it uses as much as digits as its factorization.

1201636121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171662310.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 1201636121 is about 34664.6234798533. The cubic root of 1201636121 is about 1063.1413048565.

Adding to 1201636121 its reverse (1216361021), we get a palindrome (2417997142).

The spelling of 1201636121 in words is "one billion, two hundred one million, six hundred thirty-six thousand, one hundred twenty-one".