21202056464 has 20 divisors (see below), whose sum is σ = 43495395804. Its totient is φ = 9977438208.

The previous prime is 21202056439. The next prime is 21202056467. The reversal of 21202056464 is 46465020212.

It can be written as a sum of positive squares in 2 ways, for example, as 18959086864 + 2242969600 = 137692^2 + 47360^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21202056464.

It is not an unprimeable number, because it can be changed into a prime (21202056467) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38974097 + ... + 38974640.

Almost surely, 2^21202056464 is an apocalyptic number.

It is an amenable number.

21202056464 is an abundant number, since it is smaller than the sum of its proper divisors (22293339340).

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

21202056464 is a wasteful number, since it uses less digits than its factorization.

21202056464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77948762 (or 77948756 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 32.

Adding to 21202056464 its reverse (46465020212), we get a palindrome (67667076676).

The spelling of 21202056464 in words is "twenty-one billion, two hundred two million, fifty-six thousand, four hundred sixty-four".