21642007 has 16 divisors (see below), whose sum is σ = 23569920. Its totient is φ = 19807200.

The previous prime is 21641993. The next prime is 21642013. The reversal of 21642007 is 70024612.

It is a cyclic number.

It is not a de Polignac number, because 21642007 - 2¹⁵ = 21609239 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a 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 in 15 ways as a sum of consecutive naturals, for example, 82158 + ... + 82420.

It is an arithmetic number, because the mean of its divisors is an integer number (1473120).

Almost surely, 2^21642007 is an apocalyptic number.

21642007 is a deficient number, since it is larger than the sum of its proper divisors (1927913).

21642007 is a wasteful number, since it uses less digits than its factorization.

21642007 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 414.

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 21642007 is about 4652.0970540177. The cubic root of 21642007 is about 278.6757494261.

Adding to 21642007 its reverse (70024612), we get a palindrome (91666619).

The spelling of 21642007 in words is "twenty-one million, six hundred forty-two thousand, seven".