21850609 has 12 divisors (see below), whose sum is σ = 24515568. Its totient is φ = 19314000.

The previous prime is 21850607. The next prime is 21850637. The reversal of 21850609 is 90605812.

It is not a de Polignac number, because 21850609 - 2¹ = 21850607 is a prime.

It is a super-2 number, since 2×21850609² = 954898227341762, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21850603) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14334 + ... + 15784.

It is an arithmetic number, because the mean of its divisors is an integer number (2042964).

Almost surely, 2^21850609 is an apocalyptic number.

It is an amenable number.

21850609 is a deficient number, since it is larger than the sum of its proper divisors (2664959).

21850609 is a wasteful number, since it uses less digits than its factorization.

21850609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1536 (or 1499 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 21850609 is about 4674.4634986274. The cubic root of 21850609 is about 279.5682504167.

The spelling of 21850609 in words is "twenty-one million, eight hundred fifty thousand, six hundred nine".