72380821 has 4 divisors (see below), whose sum is σ = 72407692. Its totient is φ = 72353952.

The previous prime is 72380801. The next prime is 72380851. The reversal of 72380821 is 12808327.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 62583921 + 9796900 = 7911^2 + 3130^2 .

It is a cyclic number.

It is not a de Polignac number, because 72380821 - 2²¹ = 70283669 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 (72380801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8880 + ... + 14953.

It is an arithmetic number, because the mean of its divisors is an integer number (18101923).

Almost surely, 2^72380821 is an apocalyptic number.

It is an amenable number.

72380821 is a deficient number, since it is larger than the sum of its proper divisors (26871).

72380821 is a wasteful number, since it uses less digits than its factorization.

72380821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26870.

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 72380821 is about 8507.6918726527. The cubic root of 72380821 is about 416.7489378522.

The spelling of 72380821 in words is "seventy-two million, three hundred eighty thousand, eight hundred twenty-one".