1213121001 has 4 divisors (see below), whose sum is σ = 1617494672. Its totient is φ = 808747332.

The previous prime is 1213120973. The next prime is 1213121009. The reversal of 1213121001 is 1001213121.

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: 1001213121 = 3 ⋅333737707.

It is not a de Polignac number, because 1213121001 - 2¹⁷ = 1212989929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1213121009) 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, 202186831 + ... + 202186836.

It is an arithmetic number, because the mean of its divisors is an integer number (404373668).

Almost surely, 2^1213121001 is an apocalyptic number.

It is an amenable number.

1213121001 is a deficient number, since it is larger than the sum of its proper divisors (404373671).

1213121001 is an equidigital number, since it uses as much as digits as its factorization.

1213121001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404373670.

The product of its (nonzero) digits is 12, while the sum is 12.

The square root of 1213121001 is about 34829.8866061892. The cubic root of 1213121001 is about 1066.5176335511.

Adding to 1213121001 its reverse (1001213121), we get a palindrome (2214334122).

The spelling of 1213121001 in words is "one billion, two hundred thirteen million, one hundred twenty-one thousand, one".