215288761 has 2 divisors, whose sum is σ = 215288762. Its totient is φ = 215288760.

The previous prime is 215288729. The next prime is 215288767. The reversal of 215288761 is 167882512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 185477161 + 29811600 = 13619^2 + 5460^2 .

It is a cyclic number.

It is not a de Polignac number, because 215288761 - 2⁵ = 215288729 is a prime.

It is a super-2 number, since 2×215288761² = 92698501225830242, which contains 22 as substring.

It is equal to p_11877376 and since 215288761 and 11877376 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (215288767) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107644380 + 107644381.

It is an arithmetic number, because the mean of its divisors is an integer number (107644381).

Almost surely, 2^215288761 is an apocalyptic number.

It is an amenable number.

215288761 is a deficient number, since it is larger than the sum of its proper divisors (1).

215288761 is an equidigital number, since it uses as much as digits as its factorization.

215288761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 53760, while the sum is 40.

The square root of 215288761 is about 14672.7216630044. The cubic root of 215288761 is about 599.3407212215.

The spelling of 215288761 in words is "two hundred fifteen million, two hundred eighty-eight thousand, seven hundred sixty-one".