81722971 has 8 divisors (see below), whose sum is σ = 93844800. Its totient is φ = 70383240.

The previous prime is 81722969. The next prime is 81723041. The reversal of 81722971 is 17922718.

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 81722971 - 2¹ = 81722969 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81722971.

It is not an unprimeable number, because it can be changed into a prime (81722911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 195301 + ... + 195718.

It is an arithmetic number, because the mean of its divisors is an integer number (11730600).

Almost surely, 2^81722971 is an apocalyptic number.

81722971 is a deficient number, since it is larger than the sum of its proper divisors (12121829).

81722971 is a wasteful number, since it uses less digits than its factorization.

81722971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 391049.

The product of its digits is 14112, while the sum is 37.

The square root of 81722971 is about 9040.0758293280. The cubic root of 81722971 is about 433.9583496879.

The spelling of 81722971 in words is "eighty-one million, seven hundred twenty-two thousand, nine hundred seventy-one".