81997141 has 8 divisors (see below), whose sum is σ = 86568480. Its totient is φ = 77451408.

The previous prime is 81997133. The next prime is 81997151. The reversal of 81997141 is 14179918.

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 81997141 - 2³ = 81997133 is a prime.

It is a super-2 number, since 2×81997141² = 13447062264347762, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81997094 and 81997103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81997121) 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, 375 + ... + 12811.

It is an arithmetic number, because the mean of its divisors is an integer number (10821060).

Almost surely, 2^81997141 is an apocalyptic number.

It is an amenable number.

81997141 is a deficient number, since it is larger than the sum of its proper divisors (4571339).

81997141 is a wasteful number, since it uses less digits than its factorization.

81997141 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12803.

The product of its digits is 18144, while the sum is 40.

The square root of 81997141 is about 9055.2272748949. The cubic root of 81997141 is about 434.4430993830.

The spelling of 81997141 in words is "eighty-one million, nine hundred ninety-seven thousand, one hundred forty-one".