21010162821 has 16 divisors (see below), whose sum is σ = 28103813568. Its totient is φ = 13961696000.

The previous prime is 21010162813. The next prime is 21010162837. The reversal of 21010162821 is 12826101012.

It is a cyclic number.

It is not a de Polignac number, because 21010162821 - 2³ = 21010162813 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21010162791 and 21010162800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010162841) 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, 1884355 + ... + 1895471.

It is an arithmetic number, because the mean of its divisors is an integer number (1756488348).

Almost surely, 2^21010162821 is an apocalyptic number.

It is an amenable number.

21010162821 is a deficient number, since it is larger than the sum of its proper divisors (7093650747).

21010162821 is a wasteful number, since it uses less digits than its factorization.

21010162821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13092.

The product of its (nonzero) digits is 384, while the sum is 24.

Adding to 21010162821 its reverse (12826101012), we get a palindrome (33836263833).

The spelling of 21010162821 in words is "twenty-one billion, ten million, one hundred sixty-two thousand, eight hundred twenty-one".