81206361 has 32 divisors (see below), whose sum is σ = 128832000. Its totient is φ = 50400144.

The previous prime is 81206327. The next prime is 81206383. The reversal of 81206361 is 16360218.

81206361 = 961² + 962² + ... + 1041².

81206361 is a `hidden beast` number, since 8 + 1 + 20 + 636 + 1 = 666.

It is not a de Polignac number, because 81206361 - 2⁹ = 81205849 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (81205361) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 28926 + ... + 31608.

It is an arithmetic number, because the mean of its divisors is an integer number (4026000).

Almost surely, 2^81206361 is an apocalyptic number.

It is an amenable number.

81206361 is a deficient number, since it is larger than the sum of its proper divisors (47625639).

81206361 is a wasteful number, since it uses less digits than its factorization.

81206361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2770 (or 2764 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 81206361 is about 9011.4572073555. The cubic root of 81206361 is about 433.0419966129.

Adding to 81206361 its reverse (16360218), we get a palindrome (97566579).

The spelling of 81206361 in words is "eighty-one million, two hundred six thousand, three hundred sixty-one".