1211125545 has 24 divisors (see below), whose sum is σ = 2399182656. Its totient is φ = 553657248.

The previous prime is 1211125529. The next prime is 1211125561. The reversal of 1211125545 is 5455211121.

It is a happy number.

1211125545 is a `hidden beast` number, since 1 + 2 + 1 + 112 + 5 + 545 = 666.

It is an interprime number because it is at equal distance from previous prime (1211125529) and next prime (1211125561).

It is not a de Polignac number, because 1211125545 - 2⁴ = 1211125529 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1922107 + ... + 1922736.

It is an arithmetic number, because the mean of its divisors is an integer number (99965944).

Almost surely, 2^1211125545 is an apocalyptic number.

1211125545 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1211125545 is a deficient number, since it is larger than the sum of its proper divisors (1188057111).

1211125545 is a wasteful number, since it uses less digits than its factorization.

1211125545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3844861 (or 3844858 counting only the distinct ones).

The product of its digits is 2000, while the sum is 27.

The square root of 1211125545 is about 34801.2290731233. The cubic root of 1211125545 is about 1065.9325429848.

Adding to 1211125545 its reverse (5455211121), we get a palindrome (6666336666).

It can be divided in two parts, 1211 and 125545, that added together give a triangular number (126756 = T₅₀₃).

The spelling of 1211125545 in words is "one billion, two hundred eleven million, one hundred twenty-five thousand, five hundred forty-five".