72012821 has 4 divisors (see below), whose sum is σ = 72999372. Its totient is φ = 71026272.

The previous prime is 72012803. The next prime is 72012827. The reversal of 72012821 is 12821027.

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 41088100 + 30924721 = 6410^2 + 5561^2 .

It is a cyclic number.

It is not a de Polignac number, because 72012821 - 2¹⁴ = 71996437 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 (72012827) 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, 493166 + ... + 493311.

It is an arithmetic number, because the mean of its divisors is an integer number (18249843).

Almost surely, 2^72012821 is an apocalyptic number.

It is an amenable number.

72012821 is a deficient number, since it is larger than the sum of its proper divisors (986551).

72012821 is an equidigital number, since it uses as much as digits as its factorization.

72012821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 986550.

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 72012821 is about 8486.0368252795. The cubic root of 72012821 is about 416.0414564362.

Adding to 72012821 its reverse (12821027), we get a palindrome (84833848).

The spelling of 72012821 in words is "seventy-two million, twelve thousand, eight hundred twenty-one".