21240033401 has 4 divisors (see below), whose sum is σ = 21240815232. Its totient is φ = 21239251572.

The previous prime is 21240033379. The next prime is 21240033421. The reversal of 21240033401 is 10433004212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21240033401 - 2³⁰ = 20166291577 is a prime.

It is a super-2 number, since 2×21240033401² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21240033421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 348641 + ... + 405006.

It is an arithmetic number, because the mean of its divisors is an integer number (5310203808).

Almost surely, 2^21240033401 is an apocalyptic number.

It is an amenable number.

21240033401 is a deficient number, since it is larger than the sum of its proper divisors (781831).

21240033401 is an equidigital number, since it uses as much as digits as its factorization.

21240033401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 781830.

The product of its (nonzero) digits is 576, while the sum is 20.

Adding to 21240033401 its reverse (10433004212), we get a palindrome (31673037613).

The spelling of 21240033401 in words is "twenty-one billion, two hundred forty million, thirty-three thousand, four hundred one".