81670965 has 8 divisors (see below), whose sum is σ = 130673568. Its totient is φ = 43557840.

The previous prime is 81670943. The next prime is 81670973. The reversal of 81670965 is 56907618.

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

It is not a de Polignac number, because 81670965 - 2⁷ = 81670837 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a congruent 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, 2722351 + ... + 2722380.

It is an arithmetic number, because the mean of its divisors is an integer number (16334196).

Almost surely, 2^81670965 is an apocalyptic number.

It is an amenable number.

81670965 is a deficient number, since it is larger than the sum of its proper divisors (49002603).

81670965 is a wasteful number, since it uses less digits than its factorization.

81670965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5444739.

The product of its (nonzero) digits is 90720, while the sum is 42.

The square root of 81670965 is about 9037.1989576417. The cubic root of 81670965 is about 433.8662775461.

The spelling of 81670965 in words is "eighty-one million, six hundred seventy thousand, nine hundred sixty-five".