21010401 has 8 divisors (see below), whose sum is σ = 31126560. Its totient is φ = 14006916.

The previous prime is 21010399. The next prime is 21010403. The reversal of 21010401 is 10401012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21010399) and next prime (21010403).

It is not a de Polignac number, because 21010401 - 2¹ = 21010399 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (21010403) 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 7 ways as a sum of consecutive naturals, for example, 389055 + ... + 389108.

It is an arithmetic number, because the mean of its divisors is an integer number (3890820).

Almost surely, 2^21010401 is an apocalyptic number.

It is an amenable number.

21010401 is a deficient number, since it is larger than the sum of its proper divisors (10116159).

21010401 is an equidigital number, since it uses as much as digits as its factorization.

21010401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 778172 (or 778166 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 21010401 is about 4583.7103966110. The cubic root of 21010401 is about 275.9379586447.

Adding to 21010401 its reverse (10401012), we get a palindrome (31411413).

The spelling of 21010401 in words is "twenty-one million, ten thousand, four hundred one".