1211628871 has 4 divisors (see below), whose sum is σ = 1229712952. Its totient is φ = 1193544792.

The previous prime is 1211628851. The next prime is 1211628883. The reversal of 1211628871 is 1788261121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1788261121 = 4219 ⋅423859.

It is a cyclic number.

It is not a de Polignac number, because 1211628871 - 2²⁷ = 1077411143 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1211628871.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211628851) 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, 9041940 + ... + 9042073.

It is an arithmetic number, because the mean of its divisors is an integer number (307428238).

Almost surely, 2^1211628871 is an apocalyptic number.

1211628871 is a deficient number, since it is larger than the sum of its proper divisors (18084081).

1211628871 is an equidigital number, since it uses as much as digits as its factorization.

1211628871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18084080.

The product of its digits is 10752, while the sum is 37.

The square root of 1211628871 is about 34808.4597619602. The cubic root of 1211628871 is about 1066.0801845073.

Adding to 1211628871 its reverse (1788261121), we get a palindrome (2999889992).

The spelling of 1211628871 in words is "one billion, two hundred eleven million, six hundred twenty-eight thousand, eight hundred seventy-one".