81648188 has 6 divisors (see below), whose sum is σ = 142884336. Its totient is φ = 40824092.

The previous prime is 81648163. The next prime is 81648197. The reversal of 81648188 is 88184618.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10206020 + ... + 10206027.

It is an arithmetic number, because the mean of its divisors is an integer number (23814056).

Almost surely, 2^81648188 is an apocalyptic number.

It is an amenable number.

81648188 is a deficient number, since it is larger than the sum of its proper divisors (61236148).

81648188 is a wasteful number, since it uses less digits than its factorization.

81648188 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20412051 (or 20412049 counting only the distinct ones).

The product of its digits is 98304, while the sum is 44.

The square root of 81648188 is about 9035.9386894777. The cubic root of 81648188 is about 433.8259405221.

The spelling of 81648188 in words is "eighty-one million, six hundred forty-eight thousand, one hundred eighty-eight".