81153211 has 4 divisors (see below), whose sum is σ = 81221112. Its totient is φ = 81085312.

The previous prime is 81153209. The next prime is 81153239. The reversal of 81153211 is 11235118.

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

It is a cyclic number.

It is not a de Polignac number, because 81153211 - 2¹ = 81153209 is a prime.

It is a super-2 number, since 2×81153211² = 13171687311221042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81153311) 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, 32125 + ... + 34558.

It is an arithmetic number, because the mean of its divisors is an integer number (20305278).

Almost surely, 2^81153211 is an apocalyptic number.

81153211 is a deficient number, since it is larger than the sum of its proper divisors (67901).

81153211 is a wasteful number, since it uses less digits than its factorization.

81153211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67900.

The product of its digits is 240, while the sum is 22.

The square root of 81153211 is about 9008.5077010568. The cubic root of 81153211 is about 432.9474998885.

Adding to 81153211 its reverse (11235118), we get a palindrome (92388329).

The spelling of 81153211 in words is "eighty-one million, one hundred fifty-three thousand, two hundred eleven".