186621481 has 2 divisors, whose sum is σ = 186621482. Its totient is φ = 186621480.

The previous prime is 186621403. The next prime is 186621493. The reversal of 186621481 is 184126681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 122877225 + 63744256 = 11085^2 + 7984^2 .

It is an emirp because it is prime and its reverse (184126681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 186621481 - 2²⁷ = 52403753 is a prime.

It is a super-2 number, since 2×186621481² = 69655154341266722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 186621481.

It is not a weakly prime, because it can be changed into another prime (186621181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 93310740 + 93310741.

It is an arithmetic number, because the mean of its divisors is an integer number (93310741).

Almost surely, 2^186621481 is an apocalyptic number.

It is an amenable number.

186621481 is a deficient number, since it is larger than the sum of its proper divisors (1).

186621481 is an equidigital number, since it uses as much as digits as its factorization.

186621481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18432, while the sum is 37.

The square root of 186621481 is about 13660.9472951183. The cubic root of 186621481 is about 571.4618075401.

The spelling of 186621481 in words is "one hundred eighty-six million, six hundred twenty-one thousand, four hundred eighty-one".