21531422 has 32 divisors (see below), whose sum is σ = 36799488. Its totient is φ = 9360000.

The previous prime is 21531379. The next prime is 21531439. The reversal of 21531422 is 22413512.

It is a Smith number, since the sum of its digits (20) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 21531394 and 21531403.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 89222 + ... + 89462.

It is an arithmetic number, because the mean of its divisors is an integer number (1149984).

Almost surely, 2^21531422 is an apocalyptic number.

21531422 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21531422 is a deficient number, since it is larger than the sum of its proper divisors (15268066).

21531422 is a wasteful number, since it uses less digits than its factorization.

21531422 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 416.

The product of its digits is 480, while the sum is 20.

The square root of 21531422 is about 4640.1963320532. The cubic root of 21531422 is about 278.2002852541.

Adding to 21531422 its reverse (22413512), we get a palindrome (43944934).

The spelling of 21531422 in words is "twenty-one million, five hundred thirty-one thousand, four hundred twenty-two".