21457827 has 18 divisors (see below), whose sum is σ = 32408012. Its totient is φ = 13680216.

The previous prime is 21457823. The next prime is 21457829. The reversal of 21457827 is 72875412.

It is not a de Polignac number, because 21457827 - 2² = 21457823 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21457791 and 21457800.

It is not an unprimeable number, because it can be changed into a prime (21457823) 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, 2508 + ... + 7014.

Almost surely, 2^21457827 is an apocalyptic number.

21457827 is a deficient number, since it is larger than the sum of its proper divisors (10950185).

21457827 is a wasteful number, since it uses less digits than its factorization.

21457827 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4559 (or 4533 counting only the distinct ones).

The product of its digits is 31360, while the sum is 36.

The square root of 21457827 is about 4632.2593839292. The cubic root of 21457827 is about 277.8829579938.

The spelling of 21457827 in words is "twenty-one million, four hundred fifty-seven thousand, eight hundred twenty-seven".