21011023225 has 6 divisors (see below), whose sum is σ = 26053668830. Its totient is φ = 16808818560.

The previous prime is 21011023223. The next prime is 21011023249. The reversal of 21011023225 is 52232011012.

It can be written as a sum of positive squares in 3 ways, for example, as 6957394921 + 14053628304 = 83411^2 + 118548^2 .

It is not a de Polignac number, because 21011023225 - 2¹ = 21011023223 is a prime.

It is a super-2 number, since 2×21011023225² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21011023223) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 420220440 + ... + 420220489.

Almost surely, 2^21011023225 is an apocalyptic number.

21011023225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21011023225 is a deficient number, since it is larger than the sum of its proper divisors (5042645605).

21011023225 is an equidigital number, since it uses as much as digits as its factorization.

21011023225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840440939 (or 840440934 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

Adding to 21011023225 its reverse (52232011012), we get a palindrome (73243034237).

The spelling of 21011023225 in words is "twenty-one billion, eleven million, twenty-three thousand, two hundred twenty-five".