81019910 has 32 divisors (see below), whose sum is σ = 151437600. Its totient is φ = 31171840.

The previous prime is 81019889. The next prime is 81019927. The reversal of 81019910 is 1991018.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 142106 + ... + 142674.

It is an arithmetic number, because the mean of its divisors is an integer number (4732425).

Almost surely, 2^81019910 is an apocalyptic number.

81019910 is a deficient number, since it is larger than the sum of its proper divisors (70417690).

81019910 is a wasteful number, since it uses less digits than its factorization.

81019910 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1096.

The product of its (nonzero) digits is 648, while the sum is 29.

The square root of 81019910 is about 9001.1060431483. The cubic root of 81019910 is about 432.7103190385.

The spelling of 81019910 in words is "eighty-one million, nineteen thousand, nine hundred ten".