388638421 has 2 divisors, whose sum is σ = 388638422. Its totient is φ = 388638420.

The previous prime is 388638409. The next prime is 388638431. The reversal of 388638421 is 124836883.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 351562500 + 37075921 = 18750^2 + 6089^2 .

It is a cyclic number.

It is not a de Polignac number, because 388638421 - 2²¹ = 386541269 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (388638401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 194319210 + 194319211.

It is an arithmetic number, because the mean of its divisors is an integer number (194319211).

Almost surely, 2^388638421 is an apocalyptic number.

It is an amenable number.

388638421 is a deficient number, since it is larger than the sum of its proper divisors (1).

388638421 is an equidigital number, since it uses as much as digits as its factorization.

388638421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 221184, while the sum is 43.

The square root of 388638421 is about 19713.9144007475. The cubic root of 388638421 is about 729.7631188632.

The spelling of 388638421 in words is "three hundred eighty-eight million, six hundred thirty-eight thousand, four hundred twenty-one".