72921773 has 4 divisors (see below), whose sum is σ = 72961920. Its totient is φ = 72881628.

The previous prime is 72921767. The next prime is 72921781. The reversal of 72921773 is 37712927.

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: 37712927 = 7 ⋅5387561.

It is a cyclic number.

It is not a de Polignac number, because 72921773 - 2²² = 68727469 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 (72921713) 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, 17213 + ... + 21026.

It is an arithmetic number, because the mean of its divisors is an integer number (18240480).

Almost surely, 2^72921773 is an apocalyptic number.

It is an amenable number.

72921773 is a deficient number, since it is larger than the sum of its proper divisors (40147).

72921773 is a wasteful number, since it uses less digits than its factorization.

72921773 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40146.

The product of its digits is 37044, while the sum is 38.

The square root of 72921773 is about 8539.4246293295. The cubic root of 72921773 is about 417.7845799034.

The spelling of 72921773 in words is "seventy-two million, nine hundred twenty-one thousand, seven hundred seventy-three".