81645016 has 64 divisors (see below), whose sum is σ = 169361280. Its totient is φ = 36741120.

The previous prime is 81644993. The next prime is 81645019. The reversal of 81645016 is 61054618.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81645019) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 338656 + ... + 338896.

It is an arithmetic number, because the mean of its divisors is an integer number (2646270).

Almost surely, 2^81645016 is an apocalyptic number.

It is an amenable number.

81645016 is an abundant number, since it is smaller than the sum of its proper divisors (87716264).

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

81645016 is a wasteful number, since it uses less digits than its factorization.

81645016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 364 (or 360 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 81645016 is about 9035.7631664403. The cubic root of 81645016 is about 433.8203224603.

The spelling of 81645016 in words is "eighty-one million, six hundred forty-five thousand, sixteen".