21025867 has 2 divisors, whose sum is σ = 21025868. Its totient is φ = 21025866.

The previous prime is 21025861. The next prime is 21025883. The reversal of 21025867 is 76852012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21025867 - 2¹¹ = 21023819 is a prime.

It is not a weakly prime, because it can be changed into another prime (21025861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10512933 + 10512934.

It is an arithmetic number, because the mean of its divisors is an integer number (10512934).

Almost surely, 2^21025867 is an apocalyptic number.

21025867 is a deficient number, since it is larger than the sum of its proper divisors (1).

21025867 is an equidigital number, since it uses as much as digits as its factorization.

21025867 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 21025867 is about 4585.3971474672. The cubic root of 21025867 is about 276.0056490827.

Adding to 21025867 its reverse (76852012), we get a palindrome (97877879).

The spelling of 21025867 in words is "twenty-one million, twenty-five thousand, eight hundred sixty-seven".