21266666454 has 192 divisors, whose sum is σ = 49872957120. Its totient is φ = 6031872000.

The previous prime is 21266666419. The next prime is 21266666459. The reversal of 21266666454 is 45466666212.

It is a super-2 number, since 2×21266666454² (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 (21266666459) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 155231074 + ... + 155231210.

It is an arithmetic number, because the mean of its divisors is an integer number (259754985).

Almost surely, 2^21266666454 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21266666454, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24936478560).

21266666454 is an abundant number, since it is smaller than the sum of its proper divisors (28606290666).

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

21266666454 is a wasteful number, since it uses less digits than its factorization.

21266666454 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 367 (or 356 counting only the distinct ones).

The product of its digits is 2488320, while the sum is 48.

It can be divided in two parts, 212 and 66666454, that added together give a palindrome (66666666).

The spelling of 21266666454 in words is "twenty-one billion, two hundred sixty-six million, six hundred sixty-six thousand, four hundred fifty-four".