78721573 has 8 divisors (see below), whose sum is σ = 93070080. Its totient is φ = 65148720.

The previous prime is 78721549. The next prime is 78721597. The reversal of 78721573 is 37512787.

It is an interprime number because it is at equal distance from previous prime (78721549) and next prime (78721597).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-78721573 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 (78721073) 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 7 ways as a sum of consecutive naturals, for example, 193693 + ... + 194098.

It is an arithmetic number, because the mean of its divisors is an integer number (11633760).

Almost surely, 2^78721573 is an apocalyptic number.

It is an amenable number.

78721573 is a deficient number, since it is larger than the sum of its proper divisors (14348507).

78721573 is a wasteful number, since it uses less digits than its factorization.

78721573 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387827.

The product of its digits is 82320, while the sum is 40.

The square root of 78721573 is about 8872.5178500807. The cubic root of 78721573 is about 428.5793624933.

The spelling of 78721573 in words is "seventy-eight million, seven hundred twenty-one thousand, five hundred seventy-three".