81998470 has 16 divisors (see below), whose sum is σ = 147803040. Its totient is φ = 32753664.

The previous prime is 81998467. The next prime is 81998479. The reversal of 81998470 is 7489918.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 81998470.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81998479) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2359 + ... + 13021.

It is an arithmetic number, because the mean of its divisors is an integer number (9237690).

Almost surely, 2^81998470 is an apocalyptic number.

81998470 is a deficient number, since it is larger than the sum of its proper divisors (65804570).

81998470 is a wasteful number, since it uses less digits than its factorization.

81998470 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11439.

The product of its (nonzero) digits is 145152, while the sum is 46.

The square root of 81998470 is about 9055.3006576259. The cubic root of 81998470 is about 434.4454465045.

The spelling of 81998470 in words is "eighty-one million, nine hundred ninety-eight thousand, four hundred seventy".