72497821 has 4 divisors (see below), whose sum is σ = 79088544. Its totient is φ = 65907100.

The previous prime is 72497807. The next prime is 72497827. The reversal of 72497821 is 12879427.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12879427 = 11 ⋅1170857.

It is a cyclic number.

It is not a de Polignac number, because 72497821 - 2⁹ = 72497309 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 (72497827) 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, 3295345 + ... + 3295366.

It is an arithmetic number, because the mean of its divisors is an integer number (19772136).

Almost surely, 2^72497821 is an apocalyptic number.

It is an amenable number.

72497821 is a deficient number, since it is larger than the sum of its proper divisors (6590723).

72497821 is a wasteful number, since it uses less digits than its factorization.

72497821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6590722.

The product of its digits is 56448, while the sum is 40.

The square root of 72497821 is about 8514.5652267159. The cubic root of 72497821 is about 416.9733682843.

The spelling of 72497821 in words is "seventy-two million, four hundred ninety-seven thousand, eight hundred twenty-one".