21002054165 has 16 divisors (see below), whose sum is σ = 25585082688. Its totient is φ = 16546692096.

The previous prime is 21002054159. The next prime is 21002054207. The reversal of 21002054165 is 56145020012.

It is a cyclic number.

It is not a de Polignac number, because 21002054165 - 2⁸ = 21002053909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2633474 + ... + 2641436.

It is an arithmetic number, because the mean of its divisors is an integer number (1599067668).

Almost surely, 2^21002054165 is an apocalyptic number.

It is an amenable number.

21002054165 is a deficient number, since it is larger than the sum of its proper divisors (4583028523).

21002054165 is an equidigital number, since it uses as much as digits as its factorization.

21002054165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15908.

The product of its (nonzero) digits is 2400, while the sum is 26.

Adding to 21002054165 its reverse (56145020012), we get a palindrome (77147074177).

The spelling of 21002054165 in words is "twenty-one billion, two million, fifty-four thousand, one hundred sixty-five".