81975951 has 6 divisors (see below), whose sum is σ = 118409720. Its totient is φ = 54650628.

The previous prime is 81975947. The next prime is 81975967. The reversal of 81975951 is 15957918.

It is not a de Polignac number, because 81975951 - 2² = 81975947 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81975897 and 81975906.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81975911) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4554211 + ... + 4554228.

Almost surely, 2^81975951 is an apocalyptic number.

81975951 is a deficient number, since it is larger than the sum of its proper divisors (36433769).

81975951 is a wasteful number, since it uses less digits than its factorization.

81975951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9108445 (or 9108442 counting only the distinct ones).

The product of its digits is 113400, while the sum is 45.

The square root of 81975951 is about 9054.0571568772. The cubic root of 81975951 is about 434.4056727025.

The spelling of 81975951 in words is "eighty-one million, nine hundred seventy-five thousand, nine hundred fifty-one".