1211111255025 has 243 divisors, whose sum is σ = 2589840609291. Its totient is φ = 539441138880.

The previous prime is 1211111255017. The next prime is 1211111255041. The reversal of 1211111255025 is 5205521111121.

The square root of 1211111255025 is 1100505.

It is a perfect power (a square), and thus also a powerful number.

1211111255025 is a `hidden beast` number, since 1 + 21 + 1 + 11 + 125 + 502 + 5 = 666.

It can be written as a sum of positive squares in only one way, i.e., 436000051809 + 775111203216 = 660303^2 + 880404^2 .

It is not a de Polignac number, because 1211111255025 - 2³ = 1211111255017 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1211111255025.

It is an unprimeable number.

It is a polite number, since it can be written in 242 ways as a sum of consecutive naturals, for example, 5430992064 + ... + 5430992286.

Almost surely, 2^{1211111255025} is an apocalyptic number.

1211111255025 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1211111255025 is the 1100505-th square number.

1211111255025 is the 550253-rd centered octagonal number.

It is an amenable number.

1211111255025 is an abundant number, since it is smaller than the sum of its proper divisors (1378729354266).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1211111255025 is an equidigital number, since it uses as much as digits as its factorization.

1211111255025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 570 (or 285 counting only the distinct ones).

The product of its (nonzero) digits is 1000, while the sum is 27.

Adding to 1211111255025 its reverse (5205521111121), we get a palindrome (6416632366146).

The spelling of 1211111255025 in words is "one trillion, two hundred eleven billion, one hundred eleven million, two hundred fifty-five thousand, twenty-five".