215927681 has 2 divisors, whose sum is σ = 215927682. Its totient is φ = 215927680.

The previous prime is 215927653. The next prime is 215927683. The reversal of 215927681 is 186729512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 181306225 + 34621456 = 13465^2 + 5884^2 .

It is a cyclic number.

It is not a de Polignac number, because 215927681 - 2¹⁰ = 215926657 is a prime.

It is a super-2 number, since 2×215927681² = 93249526844075522, which contains 22 as substring.

Together with 215927683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (215927683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107963840 + 107963841.

It is an arithmetic number, because the mean of its divisors is an integer number (107963841).

Almost surely, 2^215927681 is an apocalyptic number.

It is an amenable number.

215927681 is a deficient number, since it is larger than the sum of its proper divisors (1).

215927681 is an equidigital number, since it uses as much as digits as its factorization.

215927681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60480, while the sum is 41.

The square root of 215927681 is about 14694.4779083845. The cubic root of 215927681 is about 599.9330304884.

The spelling of 215927681 in words is "two hundred fifteen million, nine hundred twenty-seven thousand, six hundred eighty-one".