1211004955557 has 32 divisors (see below), whose sum is σ = 1914573312000. Its totient is φ = 753863169024.

The previous prime is 1211004955541. The next prime is 1211004955577. The reversal of 1211004955557 is 7555594001121.

1211004955557 is a `hidden beast` number, since 1 + 2 + 1 + 1 + 0 + 0 + 4 + 95 + 5 + 557 = 666.

It is not a de Polignac number, because 1211004955557 - 2⁴ = 1211004955541 is a prime.

It is a super-2 number, since 2×1211004955557² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211004955507) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10328932 + ... + 10445517.

It is an arithmetic number, because the mean of its divisors is an integer number (59830416000).

Almost surely, 2^{1211004955557} is an apocalyptic number.

1211004955557 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1211004955557 is a deficient number, since it is larger than the sum of its proper divisors (703568356443).

1211004955557 is a wasteful number, since it uses less digits than its factorization.

1211004955557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20774602 (or 20774596 counting only the distinct ones).

The product of its (nonzero) digits is 315000, while the sum is 45.

Adding to 1211004955557 its reverse (7555594001121), we get a palindrome (8766598956678).

The spelling of 1211004955557 in words is "one trillion, two hundred eleven billion, four million, nine hundred fifty-five thousand, five hundred fifty-seven".