81616705 has 8 divisors (see below), whose sum is σ = 98028072. Its totient is φ = 65234688.

The previous prime is 81616697. The next prime is 81616727. The reversal of 81616705 is 50761618.

It can be written as a sum of positive squares in 4 ways, for example, as 13256881 + 68359824 = 3641^2 + 8268^2 .

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 81616705 - 2³ = 81616697 is a prime.

It is a super-2 number, since 2×81616705² = 13322573070114050, which contains 22 as substring.

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

It is a Duffinian 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, 664 + ... + 12793.

It is an arithmetic number, because the mean of its divisors is an integer number (12253509).

Almost surely, 2^81616705 is an apocalyptic number.

It is an amenable number.

81616705 is a deficient number, since it is larger than the sum of its proper divisors (16411367).

81616705 is a wasteful number, since it uses less digits than its factorization.

81616705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14675.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 81616705 is about 9034.1964224827. The cubic root of 81616705 is about 433.7701732182.

The spelling of 81616705 in words is "eighty-one million, six hundred sixteen thousand, seven hundred five".