81621033 has 8 divisors (see below), whose sum is σ = 117199488. Its totient is φ = 50228304.

The previous prime is 81621031. The next prime is 81621049. The reversal of 81621033 is 33012618.

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

It is not a de Polignac number, because 81621033 - 2¹ = 81621031 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81620994 and 81621012.

It is not an unprimeable number, because it can be changed into a prime (81621031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1046385 + ... + 1046462.

It is an arithmetic number, because the mean of its divisors is an integer number (14649936).

Almost surely, 2^81621033 is an apocalyptic number.

It is an amenable number.

81621033 is a deficient number, since it is larger than the sum of its proper divisors (35578455).

81621033 is a wasteful number, since it uses less digits than its factorization.

81621033 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2092863.

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 81621033 is about 9034.4359536166. The cubic root of 81621033 is about 433.7778404563. Note that the first 3 decimals are identical.

The spelling of 81621033 in words is "eighty-one million, six hundred twenty-one thousand, thirty-three".