21151339225 has 81 divisors (see below), whose sum is σ = 29352436087. Its totient is φ = 15115932160.

The previous prime is 21151339217. The next prime is 21151339247. The reversal of 21151339225 is 52293315112.

The square root of 21151339225 is 145435.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 13 ways, for example, as 6891158169 + 14260181056 = 83013^2 + 119416^2 .

It is not a de Polignac number, because 21151339225 - 2³ = 21151339217 is a prime.

It is a super-2 number, since 2×21151339225² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 358497246 + ... + 358497304.

Almost surely, 2^21151339225 is an apocalyptic number.

21151339225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21151339225 is the 145435-th square number.

21151339225 is the 72718-th centered octagonal number.

It is an amenable number.

21151339225 is a deficient number, since it is larger than the sum of its proper divisors (8201096862).

21151339225 is an equidigital number, since it uses as much as digits as its factorization.

21151339225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220 (or 110 counting only the distinct ones).

The product of its digits is 16200, while the sum is 34.

The spelling of 21151339225 in words is "twenty-one billion, one hundred fifty-one million, three hundred thirty-nine thousand, two hundred twenty-five".