72136821 has 8 divisors (see below), whose sum is σ = 96720480. Its totient is φ = 47822192.

The previous prime is 72136811. The next prime is 72136829. The reversal of 72136821 is 12863127.

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 72136821 - 2⁷ = 72136693 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72136829) 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 7 ways as a sum of consecutive naturals, for example, 66630 + ... + 67703.

It is an arithmetic number, because the mean of its divisors is an integer number (12090060).

Almost surely, 2^72136821 is an apocalyptic number.

It is an amenable number.

72136821 is a deficient number, since it is larger than the sum of its proper divisors (24583659).

72136821 is a wasteful number, since it uses less digits than its factorization.

72136821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134515.

The product of its digits is 4032, while the sum is 30.

The square root of 72136821 is about 8493.3398024570. The cubic root of 72136821 is about 416.2801155965.

Adding to 72136821 its reverse (12863127), we get a palindrome (84999948).

The spelling of 72136821 in words is "seventy-two million, one hundred thirty-six thousand, eight hundred twenty-one".