81663270 has 32 divisors (see below), whose sum is σ = 211069152. Its totient is φ = 20101632.

The previous prime is 81663227. The next prime is 81663287. The reversal of 81663270 is 7236618.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 104307 + ... + 105086.

It is an arithmetic number, because the mean of its divisors is an integer number (6595911).

Almost surely, 2^81663270 is an apocalyptic number.

81663270 is an abundant number, since it is smaller than the sum of its proper divisors (129405882).

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

81663270 is a wasteful number, since it uses less digits than its factorization.

81663270 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 209416.

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 81663270 is about 9036.7732072903. The cubic root of 81663270 is about 433.8526508924.

Adding to 81663270 its reverse (7236618), we get a palindrome (88899888).

The spelling of 81663270 in words is "eighty-one million, six hundred sixty-three thousand, two hundred seventy".