81607201 has 8 divisors (see below), whose sum is σ = 88528104. Its totient is φ = 74778240.

The previous prime is 81607199. The next prime is 81607301. The reversal of 81607201 is 10270618.

It can be written as a sum of positive squares in 4 ways, for example, as 26832400 + 54774801 = 5180^2 + 7401^2 .

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 81607201 - 2¹ = 81607199 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81607301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21130 + ... + 24691.

It is an arithmetic number, because the mean of its divisors is an integer number (11066013).

Almost surely, 2^81607201 is an apocalyptic number.

It is an amenable number.

81607201 is a deficient number, since it is larger than the sum of its proper divisors (6920903).

81607201 is a wasteful number, since it uses less digits than its factorization.

81607201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45971.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 81607201 is about 9033.6704057653. The cubic root of 81607201 is about 433.7533355224.

Adding to 81607201 its reverse (10270618), we get a palindrome (91877819).

The spelling of 81607201 in words is "eighty-one million, six hundred seven thousand, two hundred one".