81947670031 has 2 divisors, whose sum is σ = 81947670032. Its totient is φ = 81947670030.

The previous prime is 81947670029. The next prime is 81947670053. The reversal of 81947670031 is 13007674918.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81947670031 - 2¹ = 81947670029 is a prime.

It is a super-2 number, since 2×81947670031² (a number of 23 digits) contains 22 as substring.

Together with 81947670029, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81947670631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40973835015 + 40973835016.

It is an arithmetic number, because the mean of its divisors is an integer number (40973835016).

Almost surely, 2^81947670031 is an apocalyptic number.

81947670031 is a deficient number, since it is larger than the sum of its proper divisors (1).

81947670031 is an equidigital number, since it uses as much as digits as its factorization.

81947670031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 254016, while the sum is 46.

The spelling of 81947670031 in words is "eighty-one billion, nine hundred forty-seven million, six hundred seventy thousand, thirty-one".