21428779968 has 84 divisors (see below), whose sum is σ = 61453138968. Its totient is φ = 7139274240.

The previous prime is 21428779961. The next prime is 21428779991. The reversal of 21428779968 is 86997782412.

It is a super-2 number, since 2×21428779968² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21428779961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1266283 + ... + 1283093.

Almost surely, 2^21428779968 is an apocalyptic number.

It is an amenable number.

21428779968 is an abundant number, since it is smaller than the sum of its proper divisors (40024359000).

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

21428779968 is a wasteful number, since it uses less digits than its factorization.

21428779968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19042 (or 19029 counting only the distinct ones).

The product of its digits is 24385536, while the sum is 63.

The spelling of 21428779968 in words is "twenty-one billion, four hundred twenty-eight million, seven hundred seventy-nine thousand, nine hundred sixty-eight".