81203161 has 8 divisors (see below), whose sum is σ = 90465480. Its totient is φ = 72371712.

The previous prime is 81203159. The next prime is 81203173. The reversal of 81203161 is 16130218.

It can be written as a sum of positive squares in 4 ways, for example, as 20985561 + 60217600 = 4581^2 + 7760^2 .

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 81203161 - 2¹ = 81203159 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81293161) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 107320 + ... + 108073.

It is an arithmetic number, because the mean of its divisors is an integer number (11308185).

Almost surely, 2^81203161 is an apocalyptic number.

It is an amenable number.

81203161 is a deficient number, since it is larger than the sum of its proper divisors (9262319).

81203161 is a wasteful number, since it uses less digits than its factorization.

81203161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215435.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 81203161 is about 9011.2796538560. The cubic root of 81203161 is about 433.0363084189.

Adding to 81203161 its reverse (16130218), we get a palindrome (97333379).

The spelling of 81203161 in words is "eighty-one million, two hundred three thousand, one hundred sixty-one".