81997073 has 8 divisors (see below), whose sum is σ = 82807200. Its totient is φ = 81190368.

The previous prime is 81997067. The next prime is 81997081. The reversal of 81997073 is 37079918.

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 81997073 - 2⁴ = 81997057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81997033) 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, 85565 + ... + 86517.

It is an arithmetic number, because the mean of its divisors is an integer number (10350900).

Almost surely, 2^81997073 is an apocalyptic number.

It is an amenable number.

81997073 is a deficient number, since it is larger than the sum of its proper divisors (810127).

81997073 is a wasteful number, since it uses less digits than its factorization.

81997073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1711.

The product of its (nonzero) digits is 95256, while the sum is 44.

The square root of 81997073 is about 9055.2235201567. The cubic root of 81997073 is about 434.4429792888.

The spelling of 81997073 in words is "eighty-one million, nine hundred ninety-seven thousand, seventy-three".