188121649 has 4 divisors (see below), whose sum is σ = 188155764. Its totient is φ = 188087536.

The previous prime is 188121629. The next prime is 188121667. The reversal of 188121649 is 946121881.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 113039424 + 75082225 = 10632^2 + 8665^2 .

It is a cyclic number.

It is not a de Polignac number, because 188121649 - 2⁵ = 188121617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (188121629) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6682 + ... + 20515.

It is an arithmetic number, because the mean of its divisors is an integer number (47038941).

Almost surely, 2^188121649 is an apocalyptic number.

It is an amenable number.

188121649 is a deficient number, since it is larger than the sum of its proper divisors (34115).

188121649 is an equidigital number, since it uses as much as digits as its factorization.

188121649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34114.

The product of its digits is 27648, while the sum is 40.

The square root of 188121649 is about 13715.7445660088. The cubic root of 188121649 is about 572.9889661394.

The spelling of 188121649 in words is "one hundred eighty-eight million, one hundred twenty-one thousand, six hundred forty-nine".