21840101 has 16 divisors (see below), whose sum is σ = 24149760. Its totient is φ = 19673280.

The previous prime is 21840083. The next prime is 21840109. The reversal of 21840101 is 10104812.

It is a cyclic number.

It is not a de Polignac number, because 21840101 - 2¹⁴ = 21823717 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21840101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21840109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32711 + ... + 33371.

It is an arithmetic number, because the mean of its divisors is an integer number (1509360).

Almost surely, 2^21840101 is an apocalyptic number.

It is an amenable number.

21840101 is a deficient number, since it is larger than the sum of its proper divisors (2309659).

21840101 is a wasteful number, since it uses less digits than its factorization.

21840101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 764.

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 21840101 is about 4673.3393842091. The cubic root of 21840101 is about 279.5234282607.

Adding to 21840101 its reverse (10104812), we get a palindrome (31944913).

The spelling of 21840101 in words is "twenty-one million, eight hundred forty thousand, one hundred one".