215661029 has 2 divisors, whose sum is σ = 215661030. Its totient is φ = 215661028.

The previous prime is 215661011. The next prime is 215661059. The reversal of 215661029 is 920166512.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 197402500 + 18258529 = 14050^2 + 4273^2 .

It is a cyclic number.

It is not a de Polignac number, because 215661029 - 2²⁴ = 198883813 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 215660986 and 215661004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (215661059) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107830514 + 107830515.

It is an arithmetic number, because the mean of its divisors is an integer number (107830515).

Almost surely, 2^215661029 is an apocalyptic number.

It is an amenable number.

215661029 is a deficient number, since it is larger than the sum of its proper divisors (1).

215661029 is an equidigital number, since it uses as much as digits as its factorization.

215661029 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 215661029 is about 14685.4019012079. The cubic root of 215661029 is about 599.6859736374.

The spelling of 215661029 in words is "two hundred fifteen million, six hundred sixty-one thousand, twenty-nine".