21851650 has 12 divisors (see below), whose sum is σ = 40644162. Its totient is φ = 8740640.

The previous prime is 21851629. The next prime is 21851657. The reversal of 21851650 is 5615812.

It can be written as a sum of positive squares in 3 ways, for example, as 10284849 + 11566801 = 3207^2 + 3401^2 .

It is not an unprimeable number, because it can be changed into a prime (21851657) 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 5 ways as a sum of consecutive naturals, for example, 218467 + ... + 218566.

Almost surely, 2^21851650 is an apocalyptic number.

21851650 is a deficient number, since it is larger than the sum of its proper divisors (18792512).

21851650 is a wasteful number, since it uses less digits than its factorization.

21851650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 437045 (or 437040 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 28.

The square root of 21851650 is about 4674.5748469781. The cubic root of 21851650 is about 279.5726900478.

The spelling of 21851650 in words is "twenty-one million, eight hundred fifty-one thousand, six hundred fifty".