72355821 has 16 divisors (see below), whose sum is σ = 98952000. Its totient is φ = 47013120.

The previous prime is 72355817. The next prime is 72355847. The reversal of 72355821 is 12855327.

It is not a de Polignac number, because 72355821 - 2² = 72355817 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72355321) 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 15 ways as a sum of consecutive naturals, for example, 18930 + ... + 22428.

It is an arithmetic number, because the mean of its divisors is an integer number (6184500).

Almost surely, 2^72355821 is an apocalyptic number.

It is an amenable number.

72355821 is a deficient number, since it is larger than the sum of its proper divisors (26596179).

72355821 is a wasteful number, since it uses less digits than its factorization.

72355821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3676.

The product of its digits is 16800, while the sum is 33.

The square root of 72355821 is about 8506.2224870973. Note that the first 3 decimals coincide. The cubic root of 72355821 is about 416.7009512767.

The spelling of 72355821 in words is "seventy-two million, three hundred fifty-five thousand, eight hundred twenty-one".