81748009631 has 2 divisors, whose sum is σ = 81748009632. Its totient is φ = 81748009630.

The previous prime is 81748009583. The next prime is 81748009661. The reversal of 81748009631 is 13690084718.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81748009631 - 2¹⁰ = 81748008607 is a prime.

It is a super-2 number, since 2×81748009631² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81748009661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40874004815 + 40874004816.

It is an arithmetic number, because the mean of its divisors is an integer number (40874004816).

Almost surely, 2^81748009631 is an apocalyptic number.

81748009631 is a deficient number, since it is larger than the sum of its proper divisors (1).

81748009631 is an equidigital number, since it uses as much as digits as its factorization.

81748009631 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 290304, while the sum is 47.

The spelling of 81748009631 in words is "eighty-one billion, seven hundred forty-eight million, nine thousand, six hundred thirty-one".