101531509 has 2 divisors, whose sum is σ = 101531510. Its totient is φ = 101531508.

The previous prime is 101531503. The next prime is 101531513. The reversal of 101531509 is 905135101.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 89302500 + 12229009 = 9450^2 + 3497^2 .

It is a cyclic number.

It is not a de Polignac number, because 101531509 - 2⁵ = 101531477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (101531503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50765754 + 50765755.

It is an arithmetic number, because the mean of its divisors is an integer number (50765755).

Almost surely, 2^101531509 is an apocalyptic number.

It is an amenable number.

101531509 is a deficient number, since it is larger than the sum of its proper divisors (1).

101531509 is an equidigital number, since it uses as much as digits as its factorization.

101531509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 675, while the sum is 25.

The square root of 101531509 is about 10076.2844838760. The cubic root of 101531509 is about 466.5164336705.

The spelling of 101531509 in words is "one hundred one million, five hundred thirty-one thousand, five hundred nine".