721074745 has 4 divisors (see below), whose sum is σ = 865289700. Its totient is φ = 576859792.

The previous prime is 721074743. The next prime is 721074751. The reversal of 721074745 is 547470127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 547470127 = 23 ⋅23803049.

It can be written as a sum of positive squares in 2 ways, for example, as 410751289 + 310323456 = 20267^2 + 17616^2 .

It is a cyclic number.

It is not a de Polignac number, because 721074745 - 2¹ = 721074743 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (721074743) 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, 72107470 + ... + 72107479.

It is an arithmetic number, because the mean of its divisors is an integer number (216322425).

Almost surely, 2^721074745 is an apocalyptic number.

It is an amenable number.

721074745 is a deficient number, since it is larger than the sum of its proper divisors (144214955).

721074745 is a wasteful number, since it uses less digits than its factorization.

721074745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144214954.

The product of its (nonzero) digits is 54880, while the sum is 37.

The square root of 721074745 is about 26852.8349527569. The cubic root of 721074745 is about 896.7266875395.

The spelling of 721074745 in words is "seven hundred twenty-one million, seventy-four thousand, seven hundred forty-five".