21026426777664 has 896 divisors, whose sum is σ = 73122050985984. Its totient is φ = 5174378496000.

The previous prime is 21026426777659. The next prime is 21026426777669. The reversal of 21026426777664 is 46677762462012.

It is an interprime number because it is at equal distance from previous prime (21026426777659) and next prime (21026426777669).

It is a super-2 number, since 2×21026426777664² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21026426777598 and 21026426777607.

It is not an unprimeable number, because it can be changed into a prime (21026426777669) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 4717616524 + ... + 4717620980.

It is an arithmetic number, because the mean of its divisors is an integer number (81609431904).

Almost surely, 2^{21026426777664} is an apocalyptic number.

21026426777664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21026426777664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36561025492992).

21026426777664 is an abundant number, since it is smaller than the sum of its proper divisors (52095624208320).

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

21026426777664 is a wasteful number, since it uses less digits than its factorization.

21026426777664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4755 (or 4745 counting only the distinct ones).

The product of its (nonzero) digits is 56899584, while the sum is 60.

The spelling of 21026426777664 in words is "twenty-one trillion, twenty-six billion, four hundred twenty-six million, seven hundred seventy-seven thousand, six hundred sixty-four".