21771630 has 24 divisors (see below), whose sum is σ = 56606472. Its totient is φ = 5805744.

The previous prime is 21771619. The next prime is 21771671. The reversal of 21771630 is 3617712.

21771630 is a `hidden beast` number, since 21 + 7 + 7 + 1 + 630 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 21771594 and 21771603.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 120864 + ... + 121043.

It is an arithmetic number, because the mean of its divisors is an integer number (2358603).

Almost surely, 2^21771630 is an apocalyptic number.

21771630 is an abundant number, since it is smaller than the sum of its proper divisors (34834842).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21771630 is a wasteful number, since it uses less digits than its factorization.

21771630 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241920 (or 241917 counting only the distinct ones).

The product of its (nonzero) digits is 1764, while the sum is 27.

The square root of 21771630 is about 4666.0079296975. The cubic root of 21771630 is about 279.2310107371.

The spelling of 21771630 in words is "twenty-one million, seven hundred seventy-one thousand, six hundred thirty".