1531641557 has 2 divisors, whose sum is σ = 1531641558. Its totient is φ = 1531641556.

The previous prime is 1531641523. The next prime is 1531641569. The reversal of 1531641557 is 7551461351.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1237210276 + 294431281 = 35174^2 + 17159^2 .

It is a cyclic number.

It is not a de Polignac number, because 1531641557 - 2⁸ = 1531641301 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1531641557.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1531641157) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 765820778 + 765820779.

It is an arithmetic number, because the mean of its divisors is an integer number (765820779).

Almost surely, 2^1531641557 is an apocalyptic number.

It is an amenable number.

1531641557 is a deficient number, since it is larger than the sum of its proper divisors (1).

1531641557 is an equidigital number, since it uses as much as digits as its factorization.

1531641557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 63000, while the sum is 38.

The square root of 1531641557 is about 39136.1924182719. The cubic root of 1531641557 is about 1152.7073094637.

The spelling of 1531641557 in words is "one billion, five hundred thirty-one million, six hundred forty-one thousand, five hundred fifty-seven".