16186421 has 2 divisors, whose sum is σ = 16186422. Its totient is φ = 16186420.

The previous prime is 16186409. The next prime is 16186439. The reversal of 16186421 is 12468161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9084196 + 7102225 = 3014^2 + 2665^2 .

It is a cyclic number.

It is not a de Polignac number, because 16186421 - 2²² = 11992117 is a prime.

It is a super-5 number, since 5×16186421⁵ (a number of 37 digits) contains 55555 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16186441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8093210 + 8093211.

It is an arithmetic number, because the mean of its divisors is an integer number (8093211).

Almost surely, 2^16186421 is an apocalyptic number.

It is an amenable number.

16186421 is a deficient number, since it is larger than the sum of its proper divisors (1).

16186421 is an equidigital number, since it uses as much as digits as its factorization.

16186421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304, while the sum is 29.

The square root of 16186421 is about 4023.2351410277. The cubic root of 16186421 is about 252.9590824692.

The spelling of 16186421 in words is "sixteen million, one hundred eighty-six thousand, four hundred twenty-one".