21401401 has 16 divisors (see below), whose sum is σ = 25320064. Its totient is φ = 17708544.

The previous prime is 21401399. The next prime is 21401407. The reversal of 21401401 is 10410412.

It is not a de Polignac number, because 21401401 - 2¹ = 21401399 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21401407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28831 + ... + 29563.

It is an arithmetic number, because the mean of its divisors is an integer number (1582504).

Almost surely, 2^21401401 is an apocalyptic number.

It is an amenable number.

21401401 is a deficient number, since it is larger than the sum of its proper divisors (3918663).

21401401 is an equidigital number, since it uses as much as digits as its factorization.

21401401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 880.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 21401401 is about 4626.1648262897. The cubic root of 21401401 is about 277.6391683514.

Adding to 21401401 its reverse (10410412), we get a palindrome (31811813).

The spelling of 21401401 in words is "twenty-one million, four hundred one thousand, four hundred one".