21771016 has 16 divisors (see below), whose sum is σ = 43222140. Its totient is φ = 10245120.

The previous prime is 21770993. The next prime is 21771019. The reversal of 21771016 is 61017712.

It can be written as a sum of positive squares in 2 ways, for example, as 16434916 + 5336100 = 4054^2 + 2310^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21771019) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 79905 + ... + 80176.

Almost surely, 2^21771016 is an apocalyptic number.

It is an amenable number.

21771016 is a deficient number, since it is larger than the sum of its proper divisors (21451124).

21771016 is a wasteful number, since it uses less digits than its factorization.

21771016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160104 (or 160100 counting only the distinct ones).

The product of its (nonzero) digits is 588, while the sum is 25.

The square root of 21771016 is about 4665.9421342318. The cubic root of 21771016 is about 279.2283857698.

Adding to 21771016 its reverse (61017712), we get a palindrome (82788728).

The spelling of 21771016 in words is "twenty-one million, seven hundred seventy-one thousand, sixteen".