1225817491 has 2 divisors, whose sum is σ = 1225817492. Its totient is φ = 1225817490.

The previous prime is 1225817449. The next prime is 1225817557. The reversal of 1225817491 is 1947185221.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1225817491 is a prime.

It is not a weakly prime, because it can be changed into another prime (1225817441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 612908745 + 612908746.

It is an arithmetic number, because the mean of its divisors is an integer number (612908746).

Almost surely, 2^1225817491 is an apocalyptic number.

1225817491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1225817491 is an equidigital number, since it uses as much as digits as its factorization.

1225817491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40320, while the sum is 40.

The square root of 1225817491 is about 35011.6764951352. The cubic root of 1225817491 is about 1070.2254426419.

The spelling of 1225817491 in words is "one billion, two hundred twenty-five million, eight hundred seventeen thousand, four hundred ninety-one".