21415211225 has 12 divisors (see below), whose sum is σ = 27202542780. Its totient is φ = 16714310400.

The previous prime is 21415211221. The next prime is 21415211249. The reversal of 21415211225 is 52211251412.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 9643829209 + 11771382016 = 98203^2 + 108496^2 .

It is not a de Polignac number, because 21415211225 - 2² = 21415211221 is a prime.

It is a super-2 number, since 2×21415211225² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21415211194 and 21415211203.

It is not an unprimeable number, because it can be changed into a prime (21415211221) 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, 10445420 + ... + 10447469.

It is an arithmetic number, because the mean of its divisors is an integer number (2266878565).

Almost surely, 2^21415211225 is an apocalyptic number.

21415211225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21415211225 is a deficient number, since it is larger than the sum of its proper divisors (5787331555).

21415211225 is a wasteful number, since it uses less digits than its factorization.

21415211225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20892940 (or 20892935 counting only the distinct ones).

The product of its digits is 1600, while the sum is 26.

Adding to 21415211225 its reverse (52211251412), we get a palindrome (73626462637).

The spelling of 21415211225 in words is "twenty-one billion, four hundred fifteen million, two hundred eleven thousand, two hundred twenty-five".