21268026 has 48 divisors (see below), whose sum is σ = 50190504. Its totient is φ = 6469632.

The previous prime is 21268019. The next prime is 21268033. The reversal of 21268026 is 62086212.

It is an interprime number because it is at equal distance from previous prime (21268019) and next prime (21268033).

It can be written as a sum of positive squares in 4 ways, for example, as 8415801 + 12852225 = 2901^2 + 3585^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 22230 + ... + 23166.

Almost surely, 2^21268026 is an apocalyptic number.

21268026 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21268026, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25095252).

21268026 is an abundant number, since it is smaller than the sum of its proper divisors (28922478).

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

21268026 is a wasteful number, since it uses less digits than its factorization.

21268026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1055 (or 1052 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 21268026 is about 4611.7270083993. The cubic root of 21268026 is about 277.0612106080.

It can be divided in two parts, 2 and 1268026, that added together give a triangular number (1268028 = T₁₅₉₂).

The spelling of 21268026 in words is "twenty-one million, two hundred sixty-eight thousand, twenty-six".