81942707745 has 12 divisors (see below), whose sum is σ = 142034026836. Its totient is φ = 43702777440.

The previous prime is 81942707731. The next prime is 81942707747. The reversal of 81942707745 is 54770724918.

It can be written as a sum of positive squares in 2 ways, for example, as 18789007329 + 63153700416 = 137073^2 + 251304^2 .

It is not a de Polignac number, because 81942707745 - 2⁵ = 81942707713 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81942707691 and 81942707700.

It is not an unprimeable number, because it can be changed into a prime (81942707747) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 910474486 + ... + 910474575.

It is an arithmetic number, because the mean of its divisors is an integer number (11836168903).

Almost surely, 2^81942707745 is an apocalyptic number.

It is an amenable number.

81942707745 is a deficient number, since it is larger than the sum of its proper divisors (60091319091).

81942707745 is a wasteful number, since it uses less digits than its factorization.

81942707745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1820949072 (or 1820949069 counting only the distinct ones).

The product of its (nonzero) digits is 3951360, while the sum is 54.

The spelling of 81942707745 in words is "eighty-one billion, nine hundred forty-two million, seven hundred seven thousand, seven hundred forty-five".