21640283 has 8 divisors (see below), whose sum is σ = 24921600. Its totient is φ = 18406440.

The previous prime is 21640279. The next prime is 21640331. The reversal of 21640283 is 38204612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21640283 - 2² = 21640279 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21640273) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10883 + ... + 12716.

It is an arithmetic number, because the mean of its divisors is an integer number (3115200).

Almost surely, 2^21640283 is an apocalyptic number.

21640283 is a deficient number, since it is larger than the sum of its proper divisors (3281317).

21640283 is a wasteful number, since it uses less digits than its factorization.

21640283 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23737.

The product of its (nonzero) digits is 2304, while the sum is 26.

The square root of 21640283 is about 4651.9117575466. The cubic root of 21640283 is about 278.6683494693.

Adding to 21640283 its reverse (38204612), we get a palindrome (59844895).

The spelling of 21640283 in words is "twenty-one million, six hundred forty thousand, two hundred eighty-three".