1211561225 has 48 divisors (see below), whose sum is σ = 1800480000. Its totient is φ = 790732800.

The previous prime is 1211561213. The next prime is 1211561243. The reversal of 1211561225 is 5221651121.

It is a de Polignac number, because none of the positive numbers 2^k-1211561225 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1211561194 and 1211561203.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 969401 + ... + 970649.

It is an arithmetic number, because the mean of its divisors is an integer number (37510000).

Almost surely, 2^1211561225 is an apocalyptic number.

It is an amenable number.

1211561225 is a deficient number, since it is larger than the sum of its proper divisors (588918775).

1211561225 is a wasteful number, since it uses less digits than its factorization.

1211561225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1530 (or 1525 counting only the distinct ones).

The product of its digits is 1200, while the sum is 26.

The square root of 1211561225 is about 34807.4880593242. The cubic root of 1211561225 is about 1066.0603441628.

The spelling of 1211561225 in words is "one billion, two hundred eleven million, five hundred sixty-one thousand, two hundred twenty-five".