1491531547397 has 2 divisors, whose sum is σ = 1491531547398. Its totient is φ = 1491531547396.

The previous prime is 1491531547379. The next prime is 1491531547409. The reversal of 1491531547397 is 7937451351941.

Together with previous prime (1491531547379) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1463134579201 + 28396968196 = 1209601^2 + 168514^2 .

It is a cyclic number.

It is not a de Polignac number, because 1491531547397 - 2⁸ = 1491531547141 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1491531547357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 745765773698 + 745765773699.

It is an arithmetic number, because the mean of its divisors is an integer number (745765773699).

Almost surely, 2^{1491531547397} is an apocalyptic number.

It is an amenable number.

1491531547397 is a deficient number, since it is larger than the sum of its proper divisors (1).

1491531547397 is an equidigital number, since it uses as much as digits as its factorization.

1491531547397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14288400, while the sum is 59.

The spelling of 1491531547397 in words is "one trillion, four hundred ninety-one billion, five hundred thirty-one million, five hundred forty-seven thousand, three hundred ninety-seven".