21006122641 has 16 divisors (see below), whose sum is σ = 25428017664. Its totient is φ = 16940219904.

The previous prime is 21006122623. The next prime is 21006122659. The reversal of 21006122641 is 14622160012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21006122623) and next prime (21006122659).

It is a cyclic number.

It is not a de Polignac number, because 21006122641 - 2¹⁵ = 21006089873 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21006122671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 330541 + ... + 388933.

It is an arithmetic number, because the mean of its divisors is an integer number (1589251104).

Almost surely, 2^21006122641 is an apocalyptic number.

It is an amenable number.

21006122641 is a deficient number, since it is larger than the sum of its proper divisors (4421895023).

21006122641 is a wasteful number, since it uses less digits than its factorization.

21006122641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61440.

The product of its (nonzero) digits is 1152, while the sum is 25.

Adding to 21006122641 its reverse (14622160012), we get a palindrome (35628282653).

The spelling of 21006122641 in words is "twenty-one billion, six million, one hundred twenty-two thousand, six hundred forty-one".