72804821 has 4 divisors (see below), whose sum is σ = 75970272. Its totient is φ = 69639372.

The previous prime is 72804803. The next prime is 72804839. The reversal of 72804821 is 12840827.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (72804803) and next prime (72804839).

It is a cyclic number.

It is not a de Polignac number, because 72804821 - 2⁶ = 72804757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72804521) 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, 1582691 + ... + 1582736.

It is an arithmetic number, because the mean of its divisors is an integer number (18992568).

Almost surely, 2^72804821 is an apocalyptic number.

It is an amenable number.

72804821 is a deficient number, since it is larger than the sum of its proper divisors (3165451).

72804821 is a wasteful number, since it uses less digits than its factorization.

72804821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3165450.

The product of its (nonzero) digits is 7168, while the sum is 32.

The square root of 72804821 is about 8532.5741133611. The cubic root of 72804821 is about 417.5611126432.

The spelling of 72804821 in words is "seventy-two million, eight hundred four thousand, eight hundred twenty-one".