1211605025 has 12 divisors (see below), whose sum is σ = 1502830524. Its totient is φ = 969000000.

The previous prime is 1211605001. The next prime is 1211605049. The reversal of 1211605025 is 5205061121.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1211605001) and next prime (1211605049).

It can be written as a sum of positive squares in 6 ways, for example, as 45792289 + 1165812736 = 6767^2 + 34144^2 .

It is not a de Polignac number, because 1211605025 - 2¹⁰ = 1211604001 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 138275 + ... + 146775.

It is an arithmetic number, because the mean of its divisors is an integer number (125235877).

Almost surely, 2^1211605025 is an apocalyptic number.

It is an amenable number.

1211605025 is a deficient number, since it is larger than the sum of its proper divisors (291225499).

1211605025 is an equidigital number, since it uses as much as digits as its factorization.

1211605025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14212 (or 14207 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 23.

The square root of 1211605025 is about 34808.1172286006. The cubic root of 1211605025 is about 1066.0731906399.

Adding to 1211605025 its reverse (5205061121), we get a palindrome (6416666146).

The spelling of 1211605025 in words is "one billion, two hundred eleven million, six hundred five thousand, twenty-five".