81692945 has 12 divisors (see below), whose sum is σ = 98765724. Its totient is φ = 64868160.

The previous prime is 81692927. The next prime is 81692957. The reversal of 81692945 is 54929618.

It can be written as a sum of positive squares in 6 ways, for example, as 3671056 + 78021889 = 1916^2 + 8833^2 .

It is not a de Polignac number, because 81692945 - 2⁶ = 81692881 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81692896 and 81692905.

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, 193835 + ... + 194255.

It is an arithmetic number, because the mean of its divisors is an integer number (8230477).

Almost surely, 2^81692945 is an apocalyptic number.

It is an amenable number.

81692945 is a deficient number, since it is larger than the sum of its proper divisors (17072779).

81692945 is an equidigital number, since it uses as much as digits as its factorization.

81692945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 820 (or 623 counting only the distinct ones).

The product of its digits is 155520, while the sum is 44.

The square root of 81692945 is about 9038.4149606001. The cubic root of 81692945 is about 433.9051960096.

The spelling of 81692945 in words is "eighty-one million, six hundred ninety-two thousand, nine hundred forty-five".