721573394 has 4 divisors (see below), whose sum is σ = 1082360094. Its totient is φ = 360786696.

The previous prime is 721573339. The next prime is 721573399. The reversal of 721573394 is 493375127.

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

It can be written as a sum of positive squares in only one way, i.e., 616777225 + 104796169 = 24835^2 + 10237^2 .

It is not an unprimeable number, because it can be changed into a prime (721573399) 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 as a sum of consecutive naturals, namely, 180393347 + ... + 180393350.

Almost surely, 2^721573394 is an apocalyptic number.

721573394 is a deficient number, since it is larger than the sum of its proper divisors (360786700).

721573394 is a wasteful number, since it uses less digits than its factorization.

721573394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 360786699.

The product of its digits is 158760, while the sum is 41.

The square root of 721573394 is about 26862.1181964491. The cubic root of 721573394 is about 896.9333461117.

The spelling of 721573394 in words is "seven hundred twenty-one million, five hundred seventy-three thousand, three hundred ninety-four".