81680275 has 24 divisors (see below), whose sum is σ = 104747760. Its totient is φ = 63135360.

The previous prime is 81680273. The next prime is 81680293. The reversal of 81680275 is 57208618.

It is not a de Polignac number, because 81680275 - 2¹ = 81680273 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is not an unprimeable number, because it can be changed into a prime (81680273) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 209781 + ... + 210169.

It is an arithmetic number, because the mean of its divisors is an integer number (4364490).

Almost surely, 2^81680275 is an apocalyptic number.

81680275 is a deficient number, since it is larger than the sum of its proper divisors (23067485).

81680275 is a wasteful number, since it uses less digits than its factorization.

81680275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 663 (or 658 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 37.

The square root of 81680275 is about 9037.7140361930. The cubic root of 81680275 is about 433.8827629706.

The spelling of 81680275 in words is "eighty-one million, six hundred eighty thousand, two hundred seventy-five".