215220725 has 6 divisors (see below), whose sum is σ = 266873730. Its totient is φ = 172176560.

The previous prime is 215220721. The next prime is 215220737. The reversal of 215220725 is 527022512.

It can be written as a sum of positive squares in 3 ways, for example, as 217156 + 215003569 = 466^2 + 14663^2 .

It is not a de Polignac number, because 215220725 - 2² = 215220721 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 215220694 and 215220703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215220721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4304390 + ... + 4304439.

It is an arithmetic number, because the mean of its divisors is an integer number (44478955).

Almost surely, 2^215220725 is an apocalyptic number.

215220725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

215220725 is a deficient number, since it is larger than the sum of its proper divisors (51653005).

215220725 is an equidigital number, since it uses as much as digits as its factorization.

215220725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8608839 (or 8608834 counting only the distinct ones).

The product of its (nonzero) digits is 2800, while the sum is 26.

The square root of 215220725 is about 14670.4030278653. The cubic root of 215220725 is about 599.2775796045.

The spelling of 215220725 in words is "two hundred fifteen million, two hundred twenty thousand, seven hundred twenty-five".