1531515551 has 2 divisors, whose sum is σ = 1531515552. Its totient is φ = 1531515550.

The previous prime is 1531515529. The next prime is 1531515553. The reversal of 1531515551 is 1555151351.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1531515551 - 2¹⁰ = 1531514527 is a prime.

Together with 1531515553, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1531515553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 765757775 + 765757776.

It is an arithmetic number, because the mean of its divisors is an integer number (765757776).

Almost surely, 2^1531515551 is an apocalyptic number.

1531515551 is a deficient number, since it is larger than the sum of its proper divisors (1).

1531515551 is an equidigital number, since it uses as much as digits as its factorization.

1531515551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9375, while the sum is 32.

The square root of 1531515551 is about 39134.5825453652. The cubic root of 1531515551 is about 1152.6756980596.

The spelling of 1531515551 in words is "one billion, five hundred thirty-one million, five hundred fifteen thousand, five hundred fifty-one".