81745305123 has 18 divisors (see below), whose sum is σ = 113954513484. Its totient is φ = 52120177824.

The previous prime is 81745305119. The next prime is 81745305151. The reversal of 81745305123 is 32150354718.

It is a happy number.

It is not a de Polignac number, because 81745305123 - 2² = 81745305119 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81745305923) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 11386311 + ... + 11393487.

Almost surely, 2^81745305123 is an apocalyptic number.

81745305123 is a deficient number, since it is larger than the sum of its proper divisors (32209208361).

81745305123 is an frugal number, since it uses more digits than its factorization.

81745305123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14403 (or 7203 counting only the distinct ones).

The product of its (nonzero) digits is 100800, while the sum is 39.

The spelling of 81745305123 in words is "eighty-one billion, seven hundred forty-five million, three hundred five thousand, one hundred twenty-three".