21787412 has 24 divisors (see below), whose sum is σ = 39273696. Its totient is φ = 10569888.

The previous prime is 21787411. The next prime is 21787453. The reversal of 21787412 is 21478712.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21787411) 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 7 ways as a sum of consecutive naturals, for example, 33563 + ... + 34205.

It is an arithmetic number, because the mean of its divisors is an integer number (1636404).

Almost surely, 2^21787412 is an apocalyptic number.

It is an amenable number.

21787412 is a deficient number, since it is larger than the sum of its proper divisors (17486284).

21787412 is a wasteful number, since it uses less digits than its factorization.

21787412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 887 (or 885 counting only the distinct ones).

The product of its digits is 6272, while the sum is 32.

The square root of 21787412 is about 4667.6987906248. The cubic root of 21787412 is about 279.2984648723.

The spelling of 21787412 in words is "twenty-one million, seven hundred eighty-seven thousand, four hundred twelve".