21002240025 has 72 divisors (see below), whose sum is σ = 40966674840. Its totient is φ = 10223262720.

The previous prime is 21002239961. The next prime is 21002240047. The reversal of 21002240025 is 52004220012.

It can be written as a sum of positive squares in 12 ways, for example, as 16778279961 + 4223960064 = 129531^2 + 64992^2 .

It is not a de Polignac number, because 21002240025 - 2⁶ = 21002239961 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 219987 + ... + 300663.

It is an arithmetic number, because the mean of its divisors is an integer number (568981595).

Almost surely, 2^21002240025 is an apocalyptic number.

21002240025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21002240025 is a deficient number, since it is larger than the sum of its proper divisors (19964434815).

21002240025 is a wasteful number, since it uses less digits than its factorization.

21002240025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80795 (or 80787 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

Adding to 21002240025 its reverse (52004220012), we get a palindrome (73006460037).

It can be divided in two parts, 210022 and 40025, that added together give a cube (250047 = 63³).

The spelling of 21002240025 in words is "twenty-one billion, two million, two hundred forty thousand, twenty-five".