1211021055 has 24 divisors (see below), whose sum is σ = 2109773952. Its totient is φ = 642594624.

The previous prime is 1211020999. The next prime is 1211021087. The reversal of 1211021055 is 5501201121.

It is not a de Polignac number, because 1211021055 - 2⁶ = 1211020991 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 59439 + ... + 77168.

It is an arithmetic number, because the mean of its divisors is an integer number (87907248).

Almost surely, 2^1211021055 is an apocalyptic number.

1211021055 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1211021055 is a deficient number, since it is larger than the sum of its proper divisors (898752897).

1211021055 is a wasteful number, since it uses less digits than its factorization.

1211021055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136815 (or 136812 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 18.

The square root of 1211021055 is about 34799.7278006596. The cubic root of 1211021055 is about 1065.9018876176.

Adding to 1211021055 its reverse (5501201121), we get a palindrome (6712222176).

The spelling of 1211021055 in words is "one billion, two hundred eleven million, twenty-one thousand, fifty-five".