21210401 has 8 divisors (see below), whose sum is σ = 21552384. Its totient is φ = 20870640.

The previous prime is 21210389. The next prime is 21210433. The reversal of 21210401 is 10401212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21210401 - 2⁶ = 21210337 is a prime.

It is a super-3 number, since 3×21210401³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21210461) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34640 + ... + 35246.

It is an arithmetic number, because the mean of its divisors is an integer number (2694048).

Almost surely, 2^21210401 is an apocalyptic number.

It is an amenable number.

21210401 is a deficient number, since it is larger than the sum of its proper divisors (341983).

21210401 is an equidigital number, since it uses as much as digits as its factorization.

21210401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1111.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 21210401 is about 4605.4751112127. The cubic root of 21210401 is about 276.8107549323.

Adding to 21210401 its reverse (10401212), we get a palindrome (31611613).

The spelling of 21210401 in words is "twenty-one million, two hundred ten thousand, four hundred one".