21771846 has 48 divisors (see below), whose sum is σ = 50409216. Its totient is φ = 6774768.

The previous prime is 21771833. The next prime is 21771859. The reversal of 21771846 is 64817712.

It is an interprime number because it is at equal distance from previous prime (21771833) and next prime (21771859).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21771846.

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 23 ways as a sum of consecutive naturals, for example, 17191 + ... + 18413.

It is an arithmetic number, because the mean of its divisors is an integer number (1050192).

Almost surely, 2^21771846 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21771846, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25204608).

21771846 is an abundant number, since it is smaller than the sum of its proper divisors (28637370).

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

21771846 is a wasteful number, since it uses less digits than its factorization.

21771846 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1297 (or 1294 counting only the distinct ones).

The product of its digits is 18816, while the sum is 36.

The square root of 21771846 is about 4666.0310757645. The cubic root of 21771846 is about 279.2319341667.

The spelling of 21771846 in words is "twenty-one million, seven hundred seventy-one thousand, eight hundred forty-six".