81652040 has 32 divisors (see below), whose sum is σ = 184275000. Its totient is φ = 32561664.

The previous prime is 81651979. The next prime is 81652049. The reversal of 81652040 is 4025618.

It can be written as a sum of positive squares in 4 ways, for example, as 67798756 + 13853284 = 8234^2 + 3722^2 .

It is not an unprimeable number, because it can be changed into a prime (81652049) 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, 11036 + ... + 16884.

Almost surely, 2^81652040 is an apocalyptic number.

It is an amenable number.

81652040 is an abundant number, since it is smaller than the sum of its proper divisors (102622960).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81652040 is a wasteful number, since it uses less digits than its factorization.

81652040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6209 (or 6205 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 81652040 is about 9036.1518358204. The cubic root of 81652040 is about 433.8327627648.

Adding to 81652040 its reverse (4025618), we get a palindrome (85677658).

The spelling of 81652040 in words is "eighty-one million, six hundred fifty-two thousand, forty".