21650993 has 24 divisors (see below), whose sum is σ = 27818280. Its totient is φ = 16692480.

The previous prime is 21650971. The next prime is 21650999. The reversal of 21650993 is 39905612.

It can be written as a sum of positive squares in 4 ways, for example, as 47089 + 21603904 = 217^2 + 4648^2 .

It is not a de Polignac number, because 21650993 - 2⁸ = 21650737 is a prime.

It is a hoax number, since the sum of its digits (35) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21650999) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25703 + ... + 26531.

It is an arithmetic number, because the mean of its divisors is an integer number (1159095).

Almost surely, 2^21650993 is an apocalyptic number.

It is an amenable number.

21650993 is a deficient number, since it is larger than the sum of its proper divisors (6167287).

21650993 is a wasteful number, since it uses less digits than its factorization.

21650993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 897 (or 890 counting only the distinct ones).

The product of its (nonzero) digits is 14580, while the sum is 35.

The square root of 21650993 is about 4653.0627547885. The cubic root of 21650993 is about 278.7143138373.

The spelling of 21650993 in words is "twenty-one million, six hundred fifty thousand, nine hundred ninety-three".