1531517989 has 2 divisors, whose sum is σ = 1531517990. Its totient is φ = 1531517988.

The previous prime is 1531517921. The next prime is 1531517993. The reversal of 1531517989 is 9897151351.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1402877025 + 128640964 = 37455^2 + 11342^2 .

It is a cyclic number.

It is not a de Polignac number, because 1531517989 - 2²⁵ = 1497963557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1531517089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 765758994 + 765758995.

It is an arithmetic number, because the mean of its divisors is an integer number (765758995).

Almost surely, 2^1531517989 is an apocalyptic number.

It is an amenable number.

1531517989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1531517989 is an equidigital number, since it uses as much as digits as its factorization.

1531517989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 340200, while the sum is 49.

The square root of 1531517989 is about 39134.6136942733. The cubic root of 1531517989 is about 1152.6763097025.

The spelling of 1531517989 in words is "one billion, five hundred thirty-one million, five hundred seventeen thousand, nine hundred eighty-nine".