21016965424 has 80 divisors (see below), whose sum is σ = 50604316672. Its totient is φ = 8233622784.

The previous prime is 21016965421. The next prime is 21016965439. The reversal of 21016965424 is 42456961012.

It is a super-2 number, since 2×21016965424² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21016965421) 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, 79897 + ... + 220039.

Almost surely, 2^21016965424 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21016965424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25302158336).

21016965424 is an abundant number, since it is smaller than the sum of its proper divisors (29587351248).

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

21016965424 is a wasteful number, since it uses less digits than its factorization.

21016965424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140274 (or 140268 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 40.

The spelling of 21016965424 in words is "twenty-one billion, sixteen million, nine hundred sixty-five thousand, four hundred twenty-four".