1866326401 has 3 divisors (see below), whose sum is σ = 1866369603. Its totient is φ = 1866283200.

The previous prime is 1866326393. The next prime is 1866326417. The reversal of 1866326401 is 1046236681.

It is a happy number.

The square root of 1866326401 is 43201.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 1296072001 + 570254400 = 36001^2 + 23880^2 .

It is not a de Polignac number, because 1866326401 - 2³ = 1866326393 is a prime.

It is a super-2 number, since 2×1866326401² = 6966348470139225602, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1866326491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 21601 + ... + 64801.

It is an arithmetic number, because the mean of its divisors is an integer number (622123201).

Almost surely, 2^1866326401 is an apocalyptic number.

1866326401 is the 43201-st square number.

1866326401 is the 21601-st centered octagonal number.

It is an amenable number.

1866326401 is a deficient number, since it is larger than the sum of its proper divisors (43202).

1866326401 is an frugal number, since it uses more digits than its factorization.

1866326401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86402 (or 43201 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 37.

The cubic root of 1866326401 is about 1231.2016812667.

The spelling of 1866326401 in words is "one billion, eight hundred sixty-six million, three hundred twenty-six thousand, four hundred one".