21022404 has 48 divisors (see below), whose sum is σ = 55939968. Its totient is φ = 6087168.

The previous prime is 21022373. The next prime is 21022411. The reversal of 21022404 is 40422012.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1312 + ... + 6615.

It is an arithmetic number, because the mean of its divisors is an integer number (1165416).

Almost surely, 2^21022404 is an apocalyptic number.

It is an amenable number.

21022404 is an abundant number, since it is smaller than the sum of its proper divisors (34917564).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21022404 is a wasteful number, since it uses less digits than its factorization.

21022404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7964 (or 7962 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 15.

The square root of 21022404 is about 4585.0195201329. The cubic root of 21022404 is about 275.9904953669.

Adding to 21022404 its reverse (40422012), we get a palindrome (61444416).

The spelling of 21022404 in words is "twenty-one million, twenty-two thousand, four hundred four".