1211212021 has 8 divisors (see below), whose sum is σ = 1235243520. Its totient is φ = 1187224272.

The previous prime is 1211211979. The next prime is 1211212063. The reversal of 1211212021 is 1202121121.

It is an interprime number because it is at equal distance from previous prime (1211211979) and next prime (1211212063).

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

It is a cyclic number.

It is not a de Polignac number, because 1211212021 - 2⁷ = 1211211893 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211211992 and 1211212010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211212421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48100 + ... + 68818.

It is an arithmetic number, because the mean of its divisors is an integer number (154405440).

Almost surely, 2^1211212021 is an apocalyptic number.

It is an amenable number.

1211212021 is a deficient number, since it is larger than the sum of its proper divisors (24031499).

1211212021 is a wasteful number, since it uses less digits than its factorization.

1211212021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21875.

The product of its (nonzero) digits is 16, while the sum is 13.

The square root of 1211212021 is about 34802.4714783304. The cubic root of 1211212021 is about 1065.9579120555.

Adding to 1211212021 its reverse (1202121121), we get a palindrome (2413333142).

The spelling of 1211212021 in words is "one billion, two hundred eleven million, two hundred twelve thousand, twenty-one".