72725021 has 4 divisors (see below), whose sum is σ = 74498844. Its totient is φ = 70951200.

The previous prime is 72724999. The next prime is 72725033. The reversal of 72725021 is 12052727.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12052727 = 47 ⋅256441.

It can be written as a sum of positive squares in 2 ways, for example, as 29822521 + 42902500 = 5461^2 + 6550^2 .

It is a cyclic number.

It is not a de Polignac number, because 72725021 - 2¹⁰ = 72723997 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72725041) 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 3 ways as a sum of consecutive naturals, for example, 886850 + ... + 886931.

It is an arithmetic number, because the mean of its divisors is an integer number (18624711).

Almost surely, 2^72725021 is an apocalyptic number.

It is an amenable number.

72725021 is a deficient number, since it is larger than the sum of its proper divisors (1773823).

72725021 is a wasteful number, since it uses less digits than its factorization.

72725021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1773822.

The product of its (nonzero) digits is 1960, while the sum is 26.

The square root of 72725021 is about 8527.8966339889. The cubic root of 72725021 is about 417.4084965661.

Adding to 72725021 its reverse (12052727), we get a palindrome (84777748).

The spelling of 72725021 in words is "seventy-two million, seven hundred twenty-five thousand, twenty-one".