388921669 has 2 divisors, whose sum is σ = 388921670. Its totient is φ = 388921668.

The previous prime is 388921607. The next prime is 388921679. The reversal of 388921669 is 966129883.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 379080900 + 9840769 = 19470^2 + 3137^2 .

It is a cyclic number.

It is not a de Polignac number, because 388921669 - 2¹¹ = 388919621 is a prime.

It is a super-2 number, since 2×388921669² = 302520129235491122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (388921679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 194460834 + 194460835.

It is an arithmetic number, because the mean of its divisors is an integer number (194460835).

Almost surely, 2^388921669 is an apocalyptic number.

It is an amenable number.

388921669 is a deficient number, since it is larger than the sum of its proper divisors (1).

388921669 is an equidigital number, since it uses as much as digits as its factorization.

388921669 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1119744, while the sum is 52.

The square root of 388921669 is about 19721.0970536631. The cubic root of 388921669 is about 729.9403648038.

The spelling of 388921669 in words is "three hundred eighty-eight million, nine hundred twenty-one thousand, six hundred sixty-nine".