81621323 has 8 divisors (see below), whose sum is σ = 93582048. Its totient is φ = 69735744.

The previous prime is 81621269. The next prime is 81621347. The reversal of 81621323 is 32312618.

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

It is a cyclic number.

It is not a de Polignac number, because 81621323 - 2⁶ = 81621259 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81621292 and 81621301.

It is not an unprimeable number, because it can be changed into a prime (81621383) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16436 + ... + 20817.

It is an arithmetic number, because the mean of its divisors is an integer number (11697756).

Almost surely, 2^81621323 is an apocalyptic number.

81621323 is a deficient number, since it is larger than the sum of its proper divisors (11960725).

81621323 is a wasteful number, since it uses less digits than its factorization.

81621323 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37573.

The product of its digits is 1728, while the sum is 26.

The square root of 81621323 is about 9034.4520033038. The cubic root of 81621323 is about 433.7783541940.

The spelling of 81621323 in words is "eighty-one million, six hundred twenty-one thousand, three hundred twenty-three".