81749674505 has 8 divisors (see below), whose sum is σ = 98132121600. Its totient is φ = 65378064816.

The previous prime is 81749674429. The next prime is 81749674507. The reversal of 81749674505 is 50547694718.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81749674505 - 2³⁶ = 13030197769 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81749674507) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2692745 + ... + 2722934.

It is an arithmetic number, because the mean of its divisors is an integer number (12266515200).

Almost surely, 2^81749674505 is an apocalyptic number.

It is an amenable number.

81749674505 is a deficient number, since it is larger than the sum of its proper divisors (16382447095).

81749674505 is a wasteful number, since it uses less digits than its factorization.

81749674505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5418703.

The product of its (nonzero) digits is 8467200, while the sum is 56.

Adding to 81749674505 its sum of digits (56), we get a square (81749674561 = 285919²).

The spelling of 81749674505 in words is "eighty-one billion, seven hundred forty-nine million, six hundred seventy-four thousand, five hundred five".