688091401 has 2 divisors, whose sum is σ = 688091402. Its totient is φ = 688091400.

The previous prime is 688091399. The next prime is 688091413. The reversal of 688091401 is 104190886.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 580761801 + 107329600 = 24099^2 + 10360^2 .

It is a cyclic number.

It is not a de Polignac number, because 688091401 - 2¹ = 688091399 is a prime.

It is a super-2 number, since 2×688091401² = 946939552260285602, which contains 22 as substring.

Together with 688091399, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (688091491) 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, 344045700 + 344045701.

It is an arithmetic number, because the mean of its divisors is an integer number (344045701).

Almost surely, 2^688091401 is an apocalyptic number.

It is an amenable number.

688091401 is a deficient number, since it is larger than the sum of its proper divisors (1).

688091401 is an equidigital number, since it uses as much as digits as its factorization.

688091401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 37.

The square root of 688091401 is about 26231.4963545734. The cubic root of 688091401 is about 882.8400842135.

The spelling of 688091401 in words is "six hundred eighty-eight million, ninety-one thousand, four hundred one".