1213212121 has 8 divisors (see below), whose sum is σ = 1324764288. Its totient is φ = 1101870000.

The previous prime is 1213212109. The next prime is 1213212137. The reversal of 1213212121 is 1212123121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1213212121 - 2¹¹ = 1213210073 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1213212095 and 1213212104.

It is not an unprimeable number, because it can be changed into a prime (1213212421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40305 + ... + 63646.

It is an arithmetic number, because the mean of its divisors is an integer number (165595536).

Almost surely, 2^1213212121 is an apocalyptic number.

1213212121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1213212121 is a deficient number, since it is larger than the sum of its proper divisors (111552167).

1213212121 is a wasteful number, since it uses less digits than its factorization.

1213212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105023.

The product of its digits is 48, while the sum is 16.

The square root of 1213212121 is about 34831.1946536434. The cubic root of 1213212121 is about 1066.5443356563.

Adding to 1213212121 its reverse (1212123121), we get a palindrome (2425335242).

The spelling of 1213212121 in words is "one billion, two hundred thirteen million, two hundred twelve thousand, one hundred twenty-one".