81222001 has 4 divisors (see below), whose sum is σ = 92825152. Its totient is φ = 69618852.

The previous prime is 81221983. The next prime is 81222007. The reversal of 81222001 is 10022218.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81222001 - 2⁷ = 81221873 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81222007) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5801565 + ... + 5801578.

It is an arithmetic number, because the mean of its divisors is an integer number (23206288).

Almost surely, 2^81222001 is an apocalyptic number.

It is an amenable number.

81222001 is a deficient number, since it is larger than the sum of its proper divisors (11603151).

81222001 is a wasteful number, since it uses less digits than its factorization.

81222001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11603150.

The product of its (nonzero) digits is 64, while the sum is 16.

The square root of 81222001 is about 9012.3249497563. The cubic root of 81222001 is about 433.0697955110.

Adding to 81222001 its reverse (10022218), we get a palindrome (91244219).

The spelling of 81222001 in words is "eighty-one million, two hundred twenty-two thousand, one".