21221827 has 12 divisors (see below), whose sum is σ = 23527168. Its totient is φ = 19126800.

The previous prime is 21221821. The next prime is 21221843. The reversal of 21221827 is 72812212.

It is a de Polignac number, because none of the positive numbers 2^k-21221827 is a prime.

It is a hoax number, since the sum of its digits (25) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221821) 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, 14677 + ... + 16057.

Almost surely, 2^21221827 is an apocalyptic number.

21221827 is a deficient number, since it is larger than the sum of its proper divisors (2305341).

21221827 is a wasteful number, since it uses less digits than its factorization.

21221827 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1530 (or 1519 counting only the distinct ones).

The product of its digits is 896, while the sum is 25.

The square root of 21221827 is about 4606.7154242475. The cubic root of 21221827 is about 276.8604518069.

The spelling of 21221827 in words is "twenty-one million, two hundred twenty-one thousand, eight hundred twenty-seven".