1265521961851 has 8 divisors (see below), whose sum is σ = 1446368789984. Its totient is φ = 1084689627840.

The previous prime is 1265521961791. The next prime is 1265521961909. The reversal of 1265521961851 is 1581691255621.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1265521961851 - 2¹³ = 1265521953659 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1265521961051) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3435780 + ... + 3786241.

It is an arithmetic number, because the mean of its divisors is an integer number (180796098748).

Almost surely, 2^{1265521961851} is an apocalyptic number.

1265521961851 is a deficient number, since it is larger than the sum of its proper divisors (180846828133).

1265521961851 is an equidigital number, since it uses as much as digits as its factorization.

1265521961851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7247061.

The product of its digits is 1296000, while the sum is 52.

The spelling of 1265521961851 in words is "one trillion, two hundred sixty-five billion, five hundred twenty-one million, nine hundred sixty-one thousand, eight hundred fifty-one".