72921847 has 4 divisors (see below), whose sum is σ = 73070856. Its totient is φ = 72772840.

The previous prime is 72921833. The next prime is 72921869. The reversal of 72921847 is 74812927.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72921847 is a prime.

It is a Smith number, since the sum of its digits (40) 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 congruent number.

It is not an unprimeable number, because it can be changed into a prime (72922847) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 73768 + ... + 74749.

It is an arithmetic number, because the mean of its divisors is an integer number (18267714).

Almost surely, 2^72921847 is an apocalyptic number.

72921847 is a deficient number, since it is larger than the sum of its proper divisors (149009).

72921847 is a wasteful number, since it uses less digits than its factorization.

72921847 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149008.

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

The square root of 72921847 is about 8539.4289621731. The cubic root of 72921847 is about 417.7847212240.

The spelling of 72921847 in words is "seventy-two million, nine hundred twenty-one thousand, eight hundred forty-seven".