81202161 has 16 divisors (see below), whose sum is σ = 111463424. Its totient is φ = 52545024.

The previous prime is 81202159. The next prime is 81202171. The reversal of 81202161 is 16120218.

It is not a de Polignac number, because 81202161 - 2¹ = 81202159 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81202111) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74160 + ... + 75246.

It is an arithmetic number, because the mean of its divisors is an integer number (6966464).

Almost surely, 2^81202161 is an apocalyptic number.

It is an amenable number.

81202161 is a deficient number, since it is larger than the sum of its proper divisors (30261263).

81202161 is a wasteful number, since it uses less digits than its factorization.

81202161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1800.

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 81202161 is about 9011.2241676700. The cubic root of 81202161 is about 433.0345308277.

Adding to 81202161 its reverse (16120218), we get a palindrome (97322379).

The spelling of 81202161 in words is "eighty-one million, two hundred two thousand, one hundred sixty-one".