81964985 has 8 divisors (see below), whose sum is σ = 102634560. Its totient is φ = 62720944.

The previous prime is 81964979. The next prime is 81965003. The reversal of 81964985 is 58946918.

It is a happy number.

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 81964985 - 2⁴ = 81964969 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 356255 + ... + 356484.

It is an arithmetic number, because the mean of its divisors is an integer number (12829320).

Almost surely, 2^81964985 is an apocalyptic number.

It is an amenable number.

81964985 is a deficient number, since it is larger than the sum of its proper divisors (20669575).

81964985 is a wasteful number, since it uses less digits than its factorization.

81964985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 712767.

The product of its digits is 622080, while the sum is 50.

The square root of 81964985 is about 9053.4515517564. The cubic root of 81964985 is about 434.3863015537.

The spelling of 81964985 in words is "eighty-one million, nine hundred sixty-four thousand, nine hundred eighty-five".