21236410164 has 12 divisors (see below), whose sum is σ = 49551623744. Its totient is φ = 7078803384.

The previous prime is 21236410121. The next prime is 21236410297. The reversal of 21236410164 is 46101463212.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 884850412 + ... + 884850435.

Almost surely, 2^21236410164 is an apocalyptic number.

It is an amenable number.

21236410164 is an abundant number, since it is smaller than the sum of its proper divisors (28315213580).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21236410164 is a wasteful number, since it uses less digits than its factorization.

21236410164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1769700854 (or 1769700852 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 30.

Adding to 21236410164 its reverse (46101463212), we get a palindrome (67337873376).

The spelling of 21236410164 in words is "twenty-one billion, two hundred thirty-six million, four hundred ten thousand, one hundred sixty-four".