21003827 has 12 divisors (see below), whose sum is σ = 23365440. Its totient is φ = 18858528.

The previous prime is 21003821. The next prime is 21003869. The reversal of 21003827 is 72830012.

It is not a de Polignac number, because 21003827 - 2⁴ = 21003811 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21003821) 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, 4574 + ... + 7932.

It is an arithmetic number, because the mean of its divisors is an integer number (1947120).

Almost surely, 2^21003827 is an apocalyptic number.

21003827 is a deficient number, since it is larger than the sum of its proper divisors (2361613).

21003827 is a wasteful number, since it uses less digits than its factorization.

21003827 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3422 (or 3409 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 21003827 is about 4582.9932358667. The cubic root of 21003827 is about 275.9091759897.

Adding to 21003827 its reverse (72830012), we get a palindrome (93833839).

The spelling of 21003827 in words is "twenty-one million, three thousand, eight hundred twenty-seven".