81299611 has 4 divisors (see below), whose sum is σ = 82328800. Its totient is φ = 80270424.

The previous prime is 81299599. The next prime is 81299623. The reversal of 81299611 is 11699218.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (81299599) and next prime (81299623).

It is a cyclic number.

It is not a de Polignac number, because 81299611 - 2¹⁷ = 81168539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81299011) 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, 514476 + ... + 514633.

It is an arithmetic number, because the mean of its divisors is an integer number (20582200).

Almost surely, 2^81299611 is an apocalyptic number.

81299611 is a deficient number, since it is larger than the sum of its proper divisors (1029189).

81299611 is a wasteful number, since it uses less digits than its factorization.

81299611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1029188.

The product of its digits is 7776, while the sum is 37.

The square root of 81299611 is about 9016.6296918527. The cubic root of 81299611 is about 433.2076885564.

The spelling of 81299611 in words is "eighty-one million, two hundred ninety-nine thousand, six hundred eleven".