1225655621 has 2 divisors, whose sum is σ = 1225655622. Its totient is φ = 1225655620.

The previous prime is 1225655611. The next prime is 1225655657. The reversal of 1225655621 is 1265565221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 925984900 + 299670721 = 30430^2 + 17311^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1225655621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1225655611) by changing a digit.

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 as a sum of consecutive naturals, namely, 612827810 + 612827811.

It is an arithmetic number, because the mean of its divisors is an integer number (612827811).

Almost surely, 2^1225655621 is an apocalyptic number.

It is an amenable number.

1225655621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1225655621 is an equidigital number, since it uses as much as digits as its factorization.

1225655621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36000, while the sum is 35.

The square root of 1225655621 is about 35009.3647614463. The cubic root of 1225655621 is about 1070.1783325788.

The spelling of 1225655621 in words is "one billion, two hundred twenty-five million, six hundred fifty-five thousand, six hundred twenty-one".