21402212525 has 12 divisors (see below), whose sum is σ = 26707785012. Its totient is φ = 17012711040.

The previous prime is 21402212521. The next prime is 21402212527. The reversal of 21402212525 is 52521220412.

It can be written as a sum of positive squares in 6 ways, for example, as 5421965956 + 15980246569 = 73634^2 + 126413^2 .

It is not a de Polignac number, because 21402212525 - 2² = 21402212521 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21402212494 and 21402212503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21402212521) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2722472 + ... + 2730321.

It is an arithmetic number, because the mean of its divisors is an integer number (2225648751).

Almost surely, 2^21402212525 is an apocalyptic number.

21402212525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21402212525 is a deficient number, since it is larger than the sum of its proper divisors (5305572487).

21402212525 is a wasteful number, since it uses less digits than its factorization.

21402212525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5452960 (or 5452955 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 26.

Adding to 21402212525 its reverse (52521220412), we get a palindrome (73923432937).

The spelling of 21402212525 in words is "twenty-one billion, four hundred two million, two hundred twelve thousand, five hundred twenty-five".