81221266 has 8 divisors (see below), whose sum is σ = 139236480. Its totient is φ = 34809108.

The previous prime is 81221233. The next prime is 81221269. The reversal of 81221266 is 66212218.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (81221269) 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, 2900746 + ... + 2900773.

It is an arithmetic number, because the mean of its divisors is an integer number (17404560).

Almost surely, 2^81221266 is an apocalyptic number.

81221266 is a deficient number, since it is larger than the sum of its proper divisors (58015214).

81221266 is a wasteful number, since it uses less digits than its factorization.

81221266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5801528.

The product of its digits is 2304, while the sum is 28.

The square root of 81221266 is about 9012.2841721730. The cubic root of 81221266 is about 433.0684891849.

The spelling of 81221266 in words is "eighty-one million, two hundred twenty-one thousand, two hundred sixty-six".