21783130 has 8 divisors (see below), whose sum is σ = 39209652. Its totient is φ = 8713248.

The previous prime is 21783119. The next prime is 21783133. The reversal of 21783130 is 3138712.

It can be written as a sum of positive squares in 2 ways, for example, as 21687649 + 95481 = 4657^2 + 309^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 21783095 and 21783104.

It is not an unprimeable number, because it can be changed into a prime (21783133) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1089147 + ... + 1089166.

Almost surely, 2^21783130 is an apocalyptic number.

21783130 is a deficient number, since it is larger than the sum of its proper divisors (17426522).

21783130 is a wasteful number, since it uses less digits than its factorization.

21783130 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2178320.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 21783130 is about 4667.2400838183. The cubic root of 21783130 is about 279.2801663186.

The spelling of 21783130 in words is "twenty-one million, seven hundred eighty-three thousand, one hundred thirty".