1264665543641 has 4 divisors (see below), whose sum is σ = 1264673798784. Its totient is φ = 1264657288500.

The previous prime is 1264665543629. The next prime is 1264665543697. The reversal of 1264665543641 is 1463455664621.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1264665543641 - 2³⁸ = 989787636697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1264665543041) 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, 3893345 + ... + 4205646.

It is an arithmetic number, because the mean of its divisors is an integer number (316168449696).

Almost surely, 2^{1264665543641} is an apocalyptic number.

It is an amenable number.

1264665543641 is a deficient number, since it is larger than the sum of its proper divisors (8255143).

1264665543641 is an equidigital number, since it uses as much as digits as its factorization.

1264665543641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8255142.

The product of its digits is 12441600, while the sum is 53.

The spelling of 1264665543641 in words is "one trillion, two hundred sixty-four billion, six hundred sixty-five million, five hundred forty-three thousand, six hundred forty-one".