21003401 has 4 divisors (see below), whose sum is σ = 21016704. Its totient is φ = 20990100.

The previous prime is 21003397. The next prime is 21003413. The reversal of 21003401 is 10430012.

It is a happy number.

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 21003401 - 2² = 21003397 is a prime.

It is a super-2 number, since 2×21003401² = 882285707133602, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21003431) 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, 3905 + ... + 7566.

It is an arithmetic number, because the mean of its divisors is an integer number (5254176).

Almost surely, 2^21003401 is an apocalyptic number.

It is an amenable number.

21003401 is a deficient number, since it is larger than the sum of its proper divisors (13303).

21003401 is a wasteful number, since it uses less digits than its factorization.

21003401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13302.

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 21003401 is about 4582.9467594551. The cubic root of 21003401 is about 275.9073106455.

Adding to 21003401 its reverse (10430012), we get a palindrome (31433413).

The spelling of 21003401 in words is "twenty-one million, three thousand, four hundred one".