1261387303225 has 27 divisors (see below), whose sum is σ = 1819543531437. Its totient is φ = 864924338880.

The previous prime is 1261387303223. The next prime is 1261387303243. The reversal of 1261387303225 is 5223037831621.

The square root of 1261387303225 is 1123115.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 680115245481 + 581272057744 = 824691^2 + 762412^2 .

It is not a de Polignac number, because 1261387303225 - 2¹ = 1261387303223 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1261387303223) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 39292981 + ... + 39325069.

Almost surely, 2^{1261387303225} is an apocalyptic number.

1261387303225 is the 1123115-th square number.

1261387303225 is the 561558-th centered octagonal number.

It is an amenable number.

1261387303225 is a deficient number, since it is larger than the sum of its proper divisors (558156228212).

1261387303225 is an frugal number, since it uses more digits than its factorization.

1261387303225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64202 (or 32101 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 43.

The spelling of 1261387303225 in words is "one trillion, two hundred sixty-one billion, three hundred eighty-seven million, three hundred three thousand, two hundred twenty-five".