21044401 has 16 divisors (see below), whose sum is σ = 25200000. Its totient is φ = 17192448.

The previous prime is 21044399. The next prime is 21044407. The reversal of 21044401 is 10444012.

It is not a de Polignac number, because 21044401 - 2¹ = 21044399 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21044407) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16225 + ... + 17473.

It is an arithmetic number, because the mean of its divisors is an integer number (1575000).

Almost surely, 2^21044401 is an apocalyptic number.

It is an amenable number.

21044401 is a deficient number, since it is larger than the sum of its proper divisors (4155599).

21044401 is a wasteful number, since it uses less digits than its factorization.

21044401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1368.

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 21044401 is about 4587.4176831852. The cubic root of 21044401 is about 276.0867236049.

Adding to 21044401 its reverse (10444012), we get a palindrome (31488413).

It can be divided in two parts, 2 and 1044401, that multiplied together give a palindrome (2088802).

The spelling of 21044401 in words is "twenty-one million, forty-four thousand, four hundred one".