688418581 has 4 divisors (see below), whose sum is σ = 710625664. Its totient is φ = 666211500.

The previous prime is 688418579. The next prime is 688418593. The reversal of 688418581 is 185814886.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 185814886 = 2 ⋅92907443.

It is a cyclic number.

It is not a de Polignac number, because 688418581 - 2¹ = 688418579 is a prime.

It is a super-2 number, since 2×688418581² = 947840285332107122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688418531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11103495 + ... + 11103556.

It is an arithmetic number, because the mean of its divisors is an integer number (177656416).

Almost surely, 2^688418581 is an apocalyptic number.

It is an amenable number.

688418581 is a deficient number, since it is larger than the sum of its proper divisors (22207083).

688418581 is a wasteful number, since it uses less digits than its factorization.

688418581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22207082.

The product of its digits is 491520, while the sum is 49.

The square root of 688418581 is about 26237.7320094554. The cubic root of 688418581 is about 882.9799890038.

The spelling of 688418581 in words is "six hundred eighty-eight million, four hundred eighteen thousand, five hundred eighty-one".