21827001 has 12 divisors (see below), whose sum is σ = 33854352. Its totient is φ = 12472488.

The previous prime is 21826999. The next prime is 21827021. The reversal of 21827001 is 10072812.

It is not a de Polignac number, because 21827001 - 2¹ = 21826999 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21827021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 74095 + ... + 74388.

It is an arithmetic number, because the mean of its divisors is an integer number (2821196).

Almost surely, 2^21827001 is an apocalyptic number.

21827001 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21827001 is a deficient number, since it is larger than the sum of its proper divisors (12027351).

21827001 is a wasteful number, since it uses less digits than its factorization.

21827001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 148500 (or 148493 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 21827001 is about 4671.9376066039. The cubic root of 21827001 is about 279.4675297207.

Adding to 21827001 its reverse (10072812), we get a palindrome (31899813).

The spelling of 21827001 in words is "twenty-one million, eight hundred twenty-seven thousand, one".