81532019531 has 2 divisors, whose sum is σ = 81532019532. Its totient is φ = 81532019530.

The previous prime is 81532019507. The next prime is 81532019539. The reversal of 81532019531 is 13591023518.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81532019531 - 2¹⁰ = 81532018507 is a prime.

It is a super-2 number, since 2×81532019531² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81532019539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40766009765 + 40766009766.

It is an arithmetic number, because the mean of its divisors is an integer number (40766009766).

Almost surely, 2^81532019531 is an apocalyptic number.

81532019531 is a deficient number, since it is larger than the sum of its proper divisors (1).

81532019531 is an equidigital number, since it uses as much as digits as its factorization.

81532019531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32400, while the sum is 38.

The spelling of 81532019531 in words is "eighty-one billion, five hundred thirty-two million, nineteen thousand, five hundred thirty-one".