688400269 has 2 divisors, whose sum is σ = 688400270. Its totient is φ = 688400268.

The previous prime is 688400249. The next prime is 688400299. The reversal of 688400269 is 962004886.

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., 372876100 + 315524169 = 19310^2 + 17763^2 .

It is a cyclic number.

It is not a de Polignac number, because 688400269 - 2⁹ = 688399757 is a prime.

It is a super-2 number, since 2×688400269² = 947789860718544722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688400239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344200134 + 344200135.

It is an arithmetic number, because the mean of its divisors is an integer number (344200135).

Almost surely, 2^688400269 is an apocalyptic number.

It is an amenable number.

688400269 is a deficient number, since it is larger than the sum of its proper divisors (1).

688400269 is an equidigital number, since it uses as much as digits as its factorization.

688400269 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 165888, while the sum is 43.

The square root of 688400269 is about 26237.3830440461. The cubic root of 688400269 is about 882.9721598171.

The spelling of 688400269 in words is "six hundred eighty-eight million, four hundred thousand, two hundred sixty-nine".