21450404 has 6 divisors (see below), whose sum is σ = 37538214. Its totient is φ = 10725200.

The previous prime is 21450389. The next prime is 21450431. The reversal of 21450404 is 40405412.

It can be written as a sum of positive squares in only one way, i.e., 20884900 + 565504 = 4570^2 + 752^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2681297 + ... + 2681304.

It is an arithmetic number, because the mean of its divisors is an integer number (6256369).

Almost surely, 2^21450404 is an apocalyptic number.

It is an amenable number.

21450404 is a deficient number, since it is larger than the sum of its proper divisors (16087810).

21450404 is a wasteful number, since it uses less digits than its factorization.

21450404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5362605 (or 5362603 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 21450404 is about 4631.4580857436. The cubic root of 21450404 is about 277.8509112089.

Adding to 21450404 its reverse (40405412), we get a palindrome (61855816).

The spelling of 21450404 in words is "twenty-one million, four hundred fifty thousand, four hundred four".