21232783 has 16 divisors (see below), whose sum is σ = 25625376. Its totient is φ = 17331840.

The previous prime is 21232781. The next prime is 21232817. The reversal of 21232783 is 38723212.

It is a cyclic number.

It is not a de Polignac number, because 21232783 - 2¹ = 21232781 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21232781) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3285 + ... + 7297.

It is an arithmetic number, because the mean of its divisors is an integer number (1601586).

Almost surely, 2^21232783 is an apocalyptic number.

21232783 is a deficient number, since it is larger than the sum of its proper divisors (4392593).

21232783 is a wasteful number, since it uses less digits than its factorization.

21232783 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4074.

The product of its digits is 4032, while the sum is 28.

The square root of 21232783 is about 4607.9044043904. The cubic root of 21232783 is about 276.9080876878.

Adding to 21232783 its reverse (38723212), we get a palindrome (59955995).

The spelling of 21232783 in words is "twenty-one million, two hundred thirty-two thousand, seven hundred eighty-three".