21270404 has 6 divisors (see below), whose sum is σ = 37223214. Its totient is φ = 10635200.

The previous prime is 21270401. The next prime is 21270407. The reversal of 21270404 is 40407212.

It is an interprime number because it is at equal distance from previous prime (21270401) and next prime (21270407).

It can be written as a sum of positive squares in only one way, i.e., 16386304 + 4884100 = 4048^2 + 2210^2 .

It is not an unprimeable number, because it can be changed into a prime (21270401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2658797 + ... + 2658804.

It is an arithmetic number, because the mean of its divisors is an integer number (6203869).

Almost surely, 2^21270404 is an apocalyptic number.

It is an amenable number.

21270404 is a deficient number, since it is larger than the sum of its proper divisors (15952810).

21270404 is a wasteful number, since it uses less digits than its factorization.

21270404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5317605 (or 5317603 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 20.

The square root of 21270404 is about 4611.9848221780. The cubic root of 21270404 is about 277.0715363901.

Adding to 21270404 its reverse (40407212), we get a palindrome (61677616).

The spelling of 21270404 in words is "twenty-one million, two hundred seventy thousand, four hundred four".