186990021 has 12 divisors (see below), whose sum is σ = 285984972. Its totient is φ = 117326976.

The previous prime is 186990007. The next prime is 186990029. The reversal of 186990021 is 120099681.

It can be written as a sum of positive squares in 2 ways, for example, as 107868996 + 79121025 = 10386^2 + 8895^2 .

It is not a de Polignac number, because 186990021 - 2¹³ = 186981829 is a prime.

It is a super-3 number, since 3×186990021³ (a number of 26 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (186990029) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 610926 + ... + 611231.

It is an arithmetic number, because the mean of its divisors is an integer number (23832081).

Almost surely, 2^186990021 is an apocalyptic number.

It is an amenable number.

186990021 is a deficient number, since it is larger than the sum of its proper divisors (98994951).

186990021 is a wasteful number, since it uses less digits than its factorization.

186990021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1222180 (or 1222177 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 186990021 is about 13674.4294579335. The cubic root of 186990021 is about 571.8377343449.

The spelling of 186990021 in words is "one hundred eighty-six million, nine hundred ninety thousand, twenty-one".