21283691 has 18 divisors (see below), whose sum is σ = 25379172. Its totient is φ = 17693520.

The previous prime is 21283679. The next prime is 21283699. The reversal of 21283691 is 19638212.

It is a de Polignac number, because none of the positive numbers 2^k-21283691 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21283699) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 198860 + ... + 198966.

It is an arithmetic number, because the mean of its divisors is an integer number (1409954).

Almost surely, 2^21283691 is an apocalyptic number.

21283691 is a deficient number, since it is larger than the sum of its proper divisors (4095481).

21283691 is a wasteful number, since it uses less digits than its factorization.

21283691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251 (or 131 counting only the distinct ones).

The product of its digits is 5184, while the sum is 32.

The square root of 21283691 is about 4613.4250833844. The cubic root of 21283691 is about 277.1292172128.

The spelling of 21283691 in words is "twenty-one million, two hundred eighty-three thousand, six hundred ninety-one".