188421907 has 2 divisors, whose sum is σ = 188421908. Its totient is φ = 188421906.

The previous prime is 188421881. The next prime is 188421923. The reversal of 188421907 is 709124881.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (709124881) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-188421907 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 188421907.

It is not a weakly prime, because it can be changed into another prime (188421967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94210953 + 94210954.

It is an arithmetic number, because the mean of its divisors is an integer number (94210954).

Almost surely, 2^188421907 is an apocalyptic number.

188421907 is a deficient number, since it is larger than the sum of its proper divisors (1).

188421907 is an equidigital number, since it uses as much as digits as its factorization.

188421907 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32256, while the sum is 40.

The square root of 188421907 is about 13726.6859438103. The cubic root of 188421907 is about 573.2936503166.

The spelling of 188421907 in words is "one hundred eighty-eight million, four hundred twenty-one thousand, nine hundred seven".