1026840491557 has 4 divisors (see below), whose sum is σ = 1038378025260. Its totient is φ = 1015302957856.

The previous prime is 1026840491539. The next prime is 1026840491597. The reversal of 1026840491557 is 7551940486201.

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 387681814881 + 639158676676 = 622641^2 + 799474^2 .

It is a cyclic number.

It is not a de Polignac number, because 1026840491557 - 2¹¹ = 1026840489509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1026840491597) 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, 5768766718 + ... + 5768766895.

It is an arithmetic number, because the mean of its divisors is an integer number (259594506315).

Almost surely, 2^{1026840491557} is an apocalyptic number.

It is an amenable number.

1026840491557 is a deficient number, since it is larger than the sum of its proper divisors (11537533703).

1026840491557 is an equidigital number, since it uses as much as digits as its factorization.

1026840491557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11537533702.

The product of its (nonzero) digits is 2419200, while the sum is 52.

The spelling of 1026840491557 in words is "one trillion, twenty-six billion, eight hundred forty million, four hundred ninety-one thousand, five hundred fifty-seven".