21012873 has 16 divisors (see below), whose sum is σ = 32126976. Its totient is φ = 11967120.

The previous prime is 21012851. The next prime is 21012877. The reversal of 21012873 is 37821012.

It is not a de Polignac number, because 21012873 - 2¹⁴ = 20996489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21012877) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5440 + ... + 8462.

It is an arithmetic number, because the mean of its divisors is an integer number (2007936).

Almost surely, 2^21012873 is an apocalyptic number.

It is an amenable number.

21012873 is a deficient number, since it is larger than the sum of its proper divisors (11114103).

21012873 is a wasteful number, since it uses less digits than its factorization.

21012873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3364.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 21012873 is about 4583.9800392236. The cubic root of 21012873 is about 275.9487801403.

Adding to 21012873 its reverse (37821012), we get a palindrome (58833885).

The spelling of 21012873 in words is "twenty-one million, twelve thousand, eight hundred seventy-three".