21521422 has 64 divisors (see below), whose sum is σ = 40279680. Its totient is φ = 8515584.

The previous prime is 21521419. The next prime is 21521431. The reversal of 21521422 is 22412512.

It is a self number, because there is not a number n which added to its sum of digits gives 21521422.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 294778 + ... + 294850.

It is an arithmetic number, because the mean of its divisors is an integer number (629370).

Almost surely, 2^21521422 is an apocalyptic number.

21521422 is a deficient number, since it is larger than the sum of its proper divisors (18758258).

21521422 is a wasteful number, since it uses less digits than its factorization.

21521422 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157.

The product of its digits is 320, while the sum is 19.

The square root of 21521422 is about 4639.1186662986. The cubic root of 21521422 is about 278.1572097023.

Adding to 21521422 its reverse (22412512), we get a palindrome (43933934).

The spelling of 21521422 in words is "twenty-one million, five hundred twenty-one thousand, four hundred twenty-two".