81738217486 has 4 divisors (see below), whose sum is σ = 122607326232. Its totient is φ = 40869108742.

The previous prime is 81738217433. The next prime is 81738217537. The reversal of 81738217486 is 68471283718.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 68471283718 = 2 ⋅34235641859.

It is a super-2 number, since 2×81738217486² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20434554370 + ... + 20434554373.

It is an arithmetic number, because the mean of its divisors is an integer number (30651831558).

Almost surely, 2^81738217486 is an apocalyptic number.

81738217486 is a deficient number, since it is larger than the sum of its proper divisors (40869108746).

81738217486 is a wasteful number, since it uses less digits than its factorization.

81738217486 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40869108745.

The product of its digits is 3612672, while the sum is 55.

The spelling of 81738217486 in words is "eighty-one billion, seven hundred thirty-eight million, two hundred seventeen thousand, four hundred eighty-six".