81628810 has 16 divisors (see below), whose sum is σ = 147210336. Its totient is φ = 32589648.

The previous prime is 81628793. The next prime is 81628829. The reversal of 81628810 is 1882618.

It is a super-2 number, since 2×81628810² = 13326525244032200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1992 + ... + 12931.

It is an arithmetic number, because the mean of its divisors is an integer number (9200646).

Almost surely, 2^81628810 is an apocalyptic number.

81628810 is a deficient number, since it is larger than the sum of its proper divisors (65581526).

81628810 is a wasteful number, since it uses less digits than its factorization.

81628810 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15477.

The product of its (nonzero) digits is 6144, while the sum is 34.

The square root of 81628810 is about 9034.8663520829. The cubic root of 81628810 is about 433.7916170651.

The spelling of 81628810 in words is "eighty-one million, six hundred twenty-eight thousand, eight hundred ten".