81632945 has 8 divisors (see below), whose sum is σ = 99565800. Its totient is φ = 64235520.

The previous prime is 81632923. The next prime is 81632977. The reversal of 81632945 is 54923618.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 73984 + 81558961 = 272^2 + 9031^2 .

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

It is not a de Polignac number, because 81632945 - 2⁸ = 81632689 is a prime.

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

It is a junction number, because it is equal to n+sod(n) for n = 81632899 and 81632908.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 133520 + ... + 134129.

It is an arithmetic number, because the mean of its divisors is an integer number (12445725).

Almost surely, 2^81632945 is an apocalyptic number.

It is an amenable number.

81632945 is a deficient number, since it is larger than the sum of its proper divisors (17932855).

81632945 is a wasteful number, since it uses less digits than its factorization.

81632945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267715.

The product of its digits is 51840, while the sum is 38.

The square root of 81632945 is about 9035.0951848888. The cubic root of 81632945 is about 433.7989416769.

The spelling of 81632945 in words is "eighty-one million, six hundred thirty-two thousand, nine hundred forty-five".