81822511945 has 12 divisors (see below), whose sum is σ = 100523547396. Its totient is φ = 63935723040.

The previous prime is 81822511933. The next prime is 81822511957. The reversal of 81822511945 is 54911522818.

It is an interprime number because it is at equal distance from previous prime (81822511933) and next prime (81822511957).

It can be written as a sum of positive squares in 2 ways, for example, as 26377332921 + 55445179024 = 162411^2 + 235468^2 .

It is not a de Polignac number, because 81822511945 - 2⁷ = 81822511817 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81822511895 and 81822511904.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4415986 + ... + 4434475.

It is an arithmetic number, because the mean of its divisors is an integer number (8376962283).

Almost surely, 2^81822511945 is an apocalyptic number.

It is an amenable number.

81822511945 is a deficient number, since it is larger than the sum of its proper divisors (18701035451).

81822511945 is an equidigital number, since it uses as much as digits as its factorization.

81822511945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8850552 (or 8850509 counting only the distinct ones).

The product of its digits is 230400, while the sum is 46.

The spelling of 81822511945 in words is "eighty-one billion, eight hundred twenty-two million, five hundred eleven thousand, nine hundred forty-five".