21642067 has 2 divisors, whose sum is σ = 21642068. Its totient is φ = 21642066.

The previous prime is 21642017. The next prime is 21642107. The reversal of 21642067 is 76024612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21642067 - 2²³ = 13253459 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21642017) 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 as a sum of consecutive naturals, namely, 10821033 + 10821034.

It is an arithmetic number, because the mean of its divisors is an integer number (10821034).

Almost surely, 2^21642067 is an apocalyptic number.

21642067 is a deficient number, since it is larger than the sum of its proper divisors (1).

21642067 is an equidigital number, since it uses as much as digits as its factorization.

21642067 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 21642067 is about 4652.1035027179. The cubic root of 21642067 is about 278.6760069581.

Adding to 21642067 its reverse (76024612), we get a palindrome (97666679).

The spelling of 21642067 in words is "twenty-one million, six hundred forty-two thousand, sixty-seven".