72321637 has 4 divisors (see below), whose sum is σ = 75466080. Its totient is φ = 69177196.

The previous prime is 72321631. The next prime is 72321659. The reversal of 72321637 is 73612327.

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: 73612327 = 19 ⋅3874333.

It is a cyclic number.

It is not a de Polignac number, because 72321637 - 2³ = 72321629 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 72321599 and 72321608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72321631) 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, 1572187 + ... + 1572232.

It is an arithmetic number, because the mean of its divisors is an integer number (18866520).

Almost surely, 2^72321637 is an apocalyptic number.

It is an amenable number.

72321637 is a deficient number, since it is larger than the sum of its proper divisors (3144443).

72321637 is a wasteful number, since it uses less digits than its factorization.

72321637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3144442.

The product of its digits is 10584, while the sum is 31.

The square root of 72321637 is about 8504.2128971469. The cubic root of 72321637 is about 416.6353184593.

The spelling of 72321637 in words is "seventy-two million, three hundred twenty-one thousand, six hundred thirty-seven".