215825684981 has 2 divisors, whose sum is σ = 215825684982. Its totient is φ = 215825684980.

The previous prime is 215825684951. The next prime is 215825684983. The reversal of 215825684981 is 189486528512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 125504398756 + 90321286225 = 354266^2 + 300535^2 .

It is a cyclic number.

It is not a de Polignac number, because 215825684981 - 2³⁰ = 214751943157 is a prime.

It is a super-2 number, since 2×215825684981² (a number of 23 digits) contains 22 as substring.

Together with 215825684983, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 215825684981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (215825684983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107912842490 + 107912842491.

It is an arithmetic number, because the mean of its divisors is an integer number (107912842491).

Almost surely, 2^215825684981 is an apocalyptic number.

It is an amenable number.

215825684981 is a deficient number, since it is larger than the sum of its proper divisors (1).

215825684981 is an equidigital number, since it uses as much as digits as its factorization.

215825684981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11059200, while the sum is 59.

The spelling of 215825684981 in words is "two hundred fifteen billion, eight hundred twenty-five million, six hundred eighty-four thousand, nine hundred eighty-one".