21838361 has 2 divisors, whose sum is σ = 21838362. Its totient is φ = 21838360.

The previous prime is 21838351. The next prime is 21838373. The reversal of 21838361 is 16383812.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14784025 + 7054336 = 3845^2 + 2656^2 .

It is a cyclic number.

It is not a de Polignac number, because 21838361 - 2¹⁴ = 21821977 is a prime.

It is a super-2 number, since 2×21838361² = 953828022332642, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (21838301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10919180 + 10919181.

It is an arithmetic number, because the mean of its divisors is an integer number (10919181).

Almost surely, 2^21838361 is an apocalyptic number.

It is an amenable number.

21838361 is a deficient number, since it is larger than the sum of its proper divisors (1).

21838361 is an equidigital number, since it uses as much as digits as its factorization.

21838361 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6912, while the sum is 32.

The square root of 21838361 is about 4673.1532181173. The cubic root of 21838361 is about 279.5160048567.

The spelling of 21838361 in words is "twenty-one million, eight hundred thirty-eight thousand, three hundred sixty-one".