215970561 has 18 divisors (see below), whose sum is σ = 317204550. Its totient is φ = 141598080.

The previous prime is 215970539. The next prime is 215970563. The reversal of 215970561 is 165079512.

215970561 is a `hidden beast` number, since 2 + 1 + 5 + 97 + 0 + 561 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 1904400 + 214066161 = 1380^2 + 14631^2 .

It is not a de Polignac number, because 215970561 - 2¹¹ = 215968513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (215970563) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 30265 + ... + 36713.

It is an arithmetic number, because the mean of its divisors is an integer number (17622475).

Almost surely, 2^215970561 is an apocalyptic number.

It is an amenable number.

215970561 is a deficient number, since it is larger than the sum of its proper divisors (101233989).

215970561 is an equidigital number, since it uses as much as digits as its factorization.

215970561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6577 (or 6513 counting only the distinct ones).

The product of its (nonzero) digits is 18900, while the sum is 36.

The square root of 215970561 is about 14695.9368874529. The cubic root of 215970561 is about 599.9727404282.

The spelling of 215970561 in words is "two hundred fifteen million, nine hundred seventy thousand, five hundred sixty-one".