1264000251265 has 4 divisors (see below), whose sum is σ = 1516800301524. Its totient is φ = 1011200201008.

The previous prime is 1264000251263. The next prime is 1264000251271. The reversal of 1264000251265 is 5621520004621.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 215973043441 + 1048027207824 = 464729^2 + 1023732^2 .

It is a cyclic number.

It is not a de Polignac number, because 1264000251265 - 2¹ = 1264000251263 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1264000251265.

It is not an unprimeable number, because it can be changed into a prime (1264000251263) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 126400025122 + ... + 126400025131.

It is an arithmetic number, because the mean of its divisors is an integer number (379200075381).

Almost surely, 2^{1264000251265} is an apocalyptic number.

It is an amenable number.

1264000251265 is a deficient number, since it is larger than the sum of its proper divisors (252800050259).

1264000251265 is an equidigital number, since it uses as much as digits as its factorization.

1264000251265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252800050258.

The product of its (nonzero) digits is 28800, while the sum is 34.

Adding to 1264000251265 its reverse (5621520004621), we get a palindrome (6885520255886).

The spelling of 1264000251265 in words is "one trillion, two hundred sixty-four billion, two hundred fifty-one thousand, two hundred sixty-five".