21653650 has 12 divisors (see below), whose sum is σ = 40275882. Its totient is φ = 8661440.

The previous prime is 21653641. The next prime is 21653657. The reversal of 21653650 is 5635612.

It can be written as a sum of positive squares in 3 ways, for example, as 17214201 + 4439449 = 4149^2 + 2107^2 .

It is not an unprimeable number, because it can be changed into a prime (21653657) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 216487 + ... + 216586.

Almost surely, 2^21653650 is an apocalyptic number.

21653650 is a deficient number, since it is larger than the sum of its proper divisors (18622232).

21653650 is a wasteful number, since it uses less digits than its factorization.

21653650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433085 (or 433080 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 21653650 is about 4653.3482569006. The cubic root of 21653650 is about 278.7257146022.

The spelling of 21653650 in words is "twenty-one million, six hundred fifty-three thousand, six hundred fifty".