81516541 has 8 divisors (see below), whose sum is σ = 83006784. Its totient is φ = 80038560.

The previous prime is 81516527. The next prime is 81516551. The reversal of 81516541 is 14561518.

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

It is not a de Polignac number, because 81516541 - 2⁵ = 81516509 is a prime.

It is a super-4 number, since 4×81516541⁴ (a number of 33 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81516511) 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, 10921 + ... + 16801.

It is an arithmetic number, because the mean of its divisors is an integer number (10375848).

Almost surely, 2^81516541 is an apocalyptic number.

It is an amenable number.

81516541 is a deficient number, since it is larger than the sum of its proper divisors (1490243).

81516541 is a wasteful number, since it uses less digits than its factorization.

81516541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6131.

The product of its digits is 4800, while the sum is 31.

The square root of 81516541 is about 9028.6511174150. The cubic root of 81516541 is about 433.5926526086.

The spelling of 81516541 in words is "eighty-one million, five hundred sixteen thousand, five hundred forty-one".