81554011 has 32 divisors (see below), whose sum is σ = 104993280. Its totient is φ = 61516800.

The previous prime is 81553987. The next prime is 81554017. The reversal of 81554011 is 11045518.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 81554011 - 2¹⁹ = 81029723 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81554017) 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, 455520 + ... + 455698.

It is an arithmetic number, because the mean of its divisors is an integer number (3281040).

Almost surely, 2^81554011 is an apocalyptic number.

81554011 is a deficient number, since it is larger than the sum of its proper divisors (23439269).

81554011 is a wasteful number, since it uses less digits than its factorization.

81554011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 355.

The product of its (nonzero) digits is 800, while the sum is 25.

The square root of 81554011 is about 9030.7259398124. The cubic root of 81554011 is about 433.6590776875.

Adding to 81554011 its reverse (11045518), we get a palindrome (92599529).

The spelling of 81554011 in words is "eighty-one million, five hundred fifty-four thousand, eleven".