688561073 has 4 divisors (see below), whose sum is σ = 689206260. Its totient is φ = 687915888.

The previous prime is 688561031. The next prime is 688561087. The reversal of 688561073 is 370165886.

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

It can be written as a sum of positive squares in 2 ways, for example, as 94322944 + 594238129 = 9712^2 + 24377^2 .

It is a cyclic number.

It is not a de Polignac number, because 688561073 - 2¹⁰ = 688560049 is a prime.

It is a super-2 number, since 2×688561073² = 948232702501822658, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (688561873) 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, 320990 + ... + 323127.

It is an arithmetic number, because the mean of its divisors is an integer number (172301565).

Almost surely, 2^688561073 is an apocalyptic number.

It is an amenable number.

688561073 is a deficient number, since it is larger than the sum of its proper divisors (645187).

688561073 is a wasteful number, since it uses less digits than its factorization.

688561073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 645186.

The product of its (nonzero) digits is 241920, while the sum is 44.

The square root of 688561073 is about 26240.4472713405. The cubic root of 688561073 is about 883.0409058686.

The spelling of 688561073 in words is "six hundred eighty-eight million, five hundred sixty-one thousand, seventy-three".