101531 has 2 divisors, whose sum is σ = 101532. Its totient is φ = 101530.

The previous prime is 101527. The next prime is 101533. The reversal of 101531 is 135101.

It is a strong prime.

It is an emirp because it is prime and its reverse (135101) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 101531 - 2² = 101527 is a prime.

It is a super-2 number, since 2×101531² = 20617087922, which contains 22 as substring.

Together with 101533, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

It is a zygodrome in base 5.

It is not a weakly prime, because it can be changed into another prime (101533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50765 + 50766.

It is an arithmetic number, because the mean of its divisors is an integer number (50766).

2¹⁰¹⁵³¹ is an apocalyptic number.

101531 is the 143-rd centered decagonal number.

101531 is a deficient number, since it is larger than the sum of its proper divisors (1).

101531 is an equidigital number, since it uses as much as digits as its factorization.

101531 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15, while the sum is 11.

The square root of 101531 is about 318.6392945009. The cubic root of 101531 is about 46.6515654086.

Adding to 101531 its reverse (135101), we get a palindrome (236632).

The spelling of 101531 in words is "one hundred one thousand, five hundred thirty-one".