72437521 has 4 divisors (see below), whose sum is σ = 78009652. Its totient is φ = 66865392.

The previous prime is 72437513. The next prime is 72437543. The reversal of 72437521 is 12573427.

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 10595025 + 61842496 = 3255^2 + 7864^2 .

It is a cyclic number.

It is not a de Polignac number, because 72437521 - 2³ = 72437513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72437501) 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, 2786046 + ... + 2786071.

It is an arithmetic number, because the mean of its divisors is an integer number (19502413).

Almost surely, 2^72437521 is an apocalyptic number.

It is an amenable number.

72437521 is a deficient number, since it is larger than the sum of its proper divisors (5572131).

72437521 is a wasteful number, since it uses less digits than its factorization.

72437521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5572130.

The product of its digits is 11760, while the sum is 31.

The square root of 72437521 is about 8511.0234989689. The cubic root of 72437521 is about 416.8577304715.

The spelling of 72437521 in words is "seventy-two million, four hundred thirty-seven thousand, five hundred twenty-one".