81998077 has 8 divisors (see below), whose sum is σ = 94678976. Its totient is φ = 69558912.

The previous prime is 81998071. The next prime is 81998143. The reversal of 81998077 is 77089918.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81998077 - 2¹¹ = 81996029 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81998077.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81998071) 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, 59703 + ... + 61060.

It is an arithmetic number, because the mean of its divisors is an integer number (11834872).

Almost surely, 2^81998077 is an apocalyptic number.

It is an amenable number.

81998077 is a deficient number, since it is larger than the sum of its proper divisors (12680899).

81998077 is a wasteful number, since it uses less digits than its factorization.

81998077 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120867.

The product of its (nonzero) digits is 254016, while the sum is 49.

The square root of 81998077 is about 9055.2789576026. The cubic root of 81998077 is about 434.4447524373. Note that the first 3 decimals are identical.

The spelling of 81998077 in words is "eighty-one million, nine hundred ninety-eight thousand, seventy-seven".