21649266 has 24 divisors (see below), whose sum is σ = 47678124. Its totient is φ = 7097760.

The previous prime is 21649247. The next prime is 21649273. The reversal of 21649266 is 66294612.

21649266 is a `hidden beast` number, since 2 + 1 + 649 + 2 + 6 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 15374241 + 6275025 = 3921^2 + 2505^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21649266.

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, 8761 + ... + 10956.

Almost surely, 2^21649266 is an apocalyptic number.

21649266 is an abundant number, since it is smaller than the sum of its proper divisors (26028858).

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

21649266 is a wasteful number, since it uses less digits than its factorization.

21649266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19786 (or 19783 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 21649266 is about 4652.8771743944. The cubic root of 21649266 is about 278.7069030546.

The spelling of 21649266 in words is "twenty-one million, six hundred forty-nine thousand, two hundred sixty-six".