688375421 has 2 divisors, whose sum is σ = 688375422. Its totient is φ = 688375420.

The previous prime is 688375403. The next prime is 688375463. The reversal of 688375421 is 124573886.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 569347321 + 119028100 = 23861^2 + 10910^2 .

It is a cyclic number.

It is not a de Polignac number, because 688375421 - 2¹⁰ = 688374397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688375921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344187710 + 344187711.

It is an arithmetic number, because the mean of its divisors is an integer number (344187711).

Almost surely, 2^688375421 is an apocalyptic number.

It is an amenable number.

688375421 is a deficient number, since it is larger than the sum of its proper divisors (1).

688375421 is an equidigital number, since it uses as much as digits as its factorization.

688375421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 322560, while the sum is 44.

The square root of 688375421 is about 26236.9095169382. The cubic root of 688375421 is about 882.9615359803.

The spelling of 688375421 in words is "six hundred eighty-eight million, three hundred seventy-five thousand, four hundred twenty-one".