1211020231 has 4 divisors (see below), whose sum is σ = 1211100264. Its totient is φ = 1210940200.

The previous prime is 1211020229. The next prime is 1211020259. The reversal of 1211020231 is 1320201121.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1320201121 = 15889 ⋅83089.

It is a cyclic number.

It is not a de Polignac number, because 1211020231 - 2¹ = 1211020229 is a prime.

It is a super-2 number, since 2×1211020231² = 2933139999782586722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211020331) 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, 9625 + ... + 50146.

It is an arithmetic number, because the mean of its divisors is an integer number (302775066).

Almost surely, 2^1211020231 is an apocalyptic number.

1211020231 is a deficient number, since it is larger than the sum of its proper divisors (80033).

1211020231 is an equidigital number, since it uses as much as digits as its factorization.

1211020231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80032.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 1211020231 is about 34799.7159614845. The cubic root of 1211020231 is about 1065.9016458648.

Adding to 1211020231 its reverse (1320201121), we get a palindrome (2531221352).

The spelling of 1211020231 in words is "one billion, two hundred eleven million, twenty thousand, two hundred thirty-one".