21025243306 has 16 divisors (see below), whose sum is σ = 33454787400. Its totient is φ = 9875934720.

The previous prime is 21025243301. The next prime is 21025243313. The reversal of 21025243306 is 60334252012.

It can be written as a sum of positive squares in 4 ways, for example, as 20508817681 + 516425625 = 143209^2 + 22725^2 .

It is a super-4 number, since 4×21025243306⁴ (a number of 42 digits) contains 4444 as substring.

It is not an unprimeable number, because it can be changed into a prime (21025243301) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 553131 + ... + 589918.

Almost surely, 2^21025243306 is an apocalyptic number.

21025243306 is a deficient number, since it is larger than the sum of its proper divisors (12429544094).

21025243306 is a wasteful number, since it uses less digits than its factorization.

21025243306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1143609.

The product of its (nonzero) digits is 8640, while the sum is 28.

Adding to 21025243306 its reverse (60334252012), we get a palindrome (81359495318).

The spelling of 21025243306 in words is "twenty-one billion, twenty-five million, two hundred forty-three thousand, three hundred six".